Thanks for the question. The reason this pattern is referenced with respect both Konica Minolta and Epson pattern appears to be a historical quirk.
First, I think there’s good reason to think this pattern did not exist pre-2000. The code 001 is found the printers that were released right after Minolta started mass producing their own inkjet printer heads, such as the Minolta Magicolor 2210.
Second, the connection between Epson and the Minolta pattern was established by the data collected by the EFF in 2005 (List of Printers Which Do or Do Not Display Tracking Dots | Electronic Frontier Foundation) and basically no similar wide-scale printer data collection project has happened since. So the data we have is very biased towards printers made between 2000-2005.
With Epson, it seems like the models that have this specific alpha dot pattern are the AcuLaser C2000 (~2001) and AcuLaser C900 / C1900 (2003).
Subsequent models use a different pattern
Epson Aculaser C3000
Epson Aculaser C4000
Epson Stylus Photo R1800
Epson Aculaser C1100
Interestingly, this youtuber https://www.youtube.com/@Abyssoft has been in contact with me and he was able to get 10+ scans of modern Epson prints from his fans (in addition to one from him and one from me). I did not find a dot pattern on any of them, which actually means that Epson seems to be one of the few companies today that actually doesn’t add yellow tracking dots. (HQ beta printed on an Epson? 
)
Anyway, the AcuLaser C900 / C1900 are related models that use the same ink drums.
They also appear to use the same drum as the Minolta Magicolor 2300DL (all three have code 005 in the dot pattern).
Likewise AcuLaser C2000 and Magicolor 2210 (code 001) also appear to have compatible drums.
So putting this all together. The alpha pattern seems to be specific to Minolta and their production facility. Often times an original equipment manufacturer (OEM) will produce things for other companies. So for a brief window in the early 2000s, it seems that some Epson printers had their main components produced by Minolta (or at least they shared some third party OEM) - note they are both Japanese. Later, Epson would change to a different OEM and today it seems that they are being produced to not leave tracking dots.
So to answer your question, no I don’t think this particular dot pattern existed before the year 2000. I don’t think Epson is associated with the pattern outside of a small number of models from the early 2000s.