I don't think they de-value a game. I just restored a TAF, and I put them on immediately.
I get the sellers thoughts that you modified it from being all original. But, in this case; its not collectors quality, so it doesn't matter.
It has extensive rust and damage; so you can't treat like its a NIB Collectors dream. You paid top dollar for what many see as a ho-hum game......
If anything the seller should overlook it, due the condition of the machine. It was not sold "as advertised".
Never, Ever, buy a machine sight unseen.........
BTW..The holes are small for the leg protectors, and you don't even see them when the leg's are on....Not sure why people make such an issue...