radio wiring harness melted together to main dash harness

[leathers2006]

I have 1990 300zx that I bought for $200 and drove it home on bill of sale, yes you will come across good deals from time to time. Anyways after closer interior inspection due to having interior piled up in trunk area I noticed that radio wiring harness had been fused into the main harness which ended up making the speaker wires themselves 12v positive. anyways having hard time trying to find harness for it in a way. Yes, I found one on ebay, here's the problem not knowing if the 1988 300zx wiring harness is interchangeable that car and mine, both have the exact same options and all. Would these two harnesses be compatible???????? Anyone please.