You mean the Stoise and Saur from the Intro Deck that includes the VHS casette? Pretty sure these are less common than the CD promos, but neither falls into the definition of what I would call particularily rare.
The CD promos numbers in the 10’s of thousands. They are by no means rare… The intro deck starters are more rare and there is also the GB Venusaur promo. None of these cards are rare or scarce, BUT they tend to have some value based on being starters and having sweet vintage artwork. The CD Charizard probably has the highest population of 10’s for ANY charizard among vintage cards (note I did not include modern in that, lol).
Technically it’s a slightly different artwork. Both are the same Ken Sugimori artwork, but the Trade Please! Campaign C Course; Intro Pack - Bulbasaur Deck; and Pokémon Song Best Collection CD versions all have a zoomed in artwork in comparison, and the background are different:
Wow I just had a look and had no idea how much lower pop the Squirtle deck Blastoise is compared to the CD promo.
Almost the same card so don’t expect much difference in value but I’m sure the Squirtle deck ones are even cheaper than the CD promo sometimes as I’m sure was the case when I picked up my PSA 9 Squirtle deck a few weeks ago