Out of curiosity, how much do you think a psa 10 1st ed prerelease aerodactyl should command over the regular version? Since the prerelease is (I would assume) technically the true rookie card for aerodactyl in English
Thinking about buying one but noticed that there seems to be NM versions everywhere for this card
Prerelease is worth less.
No idea on the PSA 10s but to give you an idea on the NMs:
Aerodactyl - 1/62 - Pre-Release Promo (Starlight Holo) $7
Aerodactyl - 1/62 - Pre-Release Promo (Galaxy Holo) $12
Aerodactyl - 1/62 - Holo 1st Edition $21
Unless the prereleases are impossibly hard to PSA 10 I can’t see there being a reversal in price.
Looking at the pop report, it would appear that 10s for both the brown stamp and gold stamp versions are pretty scarce.
One has a POP of 7
The other has a POP of 17
Unfortunately, I can’t tell which pop report applies to which stamp since PSA doesn’t indicate.
www.psacard.com/pop/tcg-cards/1999/pokemon-fossil/57617
As far as value, I checked ebay and couldn’t find any recently sold PSA 10 listings. Based on their rarity, however, I could see them commanding a higher premium than a non-prerelease PSA 10, of which there are many.
PSA 10 1st edition:
www.ebay.com/itm/Pokemon-1st-Edition-Fossil-Aerodactyl-Holo-Rare-1-64-PSA-10-GEM-MINT-/192358754753
PSA 10 1st edition:
www.ebay.com/itm/1999-Pokemon-Fossil-1st-First-Edition-Aerodactyl-Holo-PSA-10-Gem-Mint-1/253649537628?hash=item3b0eb0ca5c:g:h~8AAOSwFShaw65V
PSA 9 Prerelease:
www.ebay.com/itm/PSA-9-First-Edition-HOLO-PRERELEASE-Aerodactyl-1999-Fossil-Pokemon-Card-1-62/263334043204?hash=item3d4fee9e44:g:ImAAAOSwT2daEk3Z
PSA 9 that didn’t sell:
www.ebay.com/itm/PSA-9-MINT-Aerodactyl-1-62-1st-Edition-HOLO-Rare-PRERELEASE-1999-Fossil-Pokemon/142773593705?hash=item213df82669:g:~rEAAOSwqMRa3MOj
I’d guess that a prerelease PSA 10 would sell between $50-$100 and it just seems like no one bothers to grade them compared to the more expensive regular release 1st edition.
This is one of those instances where because 10’s are so scarce (extremely tough card to grade), that they can go for significantly more than a PSA 9. They have been known to sell in the $400-$500 range in some instances, while one went at auction for less than $100. Seems like prices are all over the map, at least according to last year’s sales (details in below thread). There’s one up on Ebay in the $300 price range, and I’d be curious to see what it eventually sells for.
www.elitefourum.com/t/prerelease-aerodactyl-psa-10-1st-edition-gold-stamp/16095/1
There are brown and gold stamped versions?
Correct! 
The brown stamp has a star foil pattern, like in Base, and the gold stamp has a cosmos holofoil pattern.
That makes a lot of sense. Price range will be all over the place since difficulty to grade and varying demand. Even though it is not a highly sought after card, if someone really wants a PSA 10 they might spend a lot on it.
Just to give some insight, I sold my PSA 10 for £275 around 3 months ago,
These are difficult to grade 10 for some reason,
9s seem to be everywhere 
Looks like the seller accepted a best offer price on the PSA 10 that was on Ebay. Would love to know what it went for.
There’s a way to see what best offers sold for! Websites like watchcount.com allow you to search for sold listing, even ones with best offers, to see what they actually sold for. The listing in question sold for 220 GBP which is a little less than $300 USD. Here is a link if you would like to see for yourself:
Wow, thanks! I didn’t know about this.
I’ve sold 3 in the past 18 month for around 400 USD each on ebay. I’ve also seen a few go for 200-250 USD at auction within that span. Hope this helps you out value-wise but I agree with the comments above, it rarely pops up for sale and is tough to grade in a 10.