I used etsy back in november to pay someone to mod my beyerdynamic DT 770 pro 80 ohm headphone cord (which was starting to wear down and expose the cords on the inside) into a removable one. Dude got it done in like a week. The site itself is legit.
https://gamefaqs.gamespot.com/a/user_image/9/7/3/AARkkPAAEtgd.jpg
Now that game cart you are looking at could possibly be a reproduction though. Usually the sellers is clear about that. (Like I have been thinking of getting a copy of star ocean 2 blue sphere for the gameboy color myself. This never released outside of japan, so the sellers on etsy made it clear that its just a repro-cart with the recent fan-translation patched onto the rom).
GTag:MadDogg730 PSN:lMadDogg NNID:xMadDoggx NS friend code:5313-0564-0819 Go buy cyber shadow like right now.