How do you know it's an 88 frame?  If it's a craigslist ad, i wouldnt trust it.  An 87 frame has many differences and the major one being you wont be able to run your 90 a-arms on it.  88-90 will all interchange.

I've dealt with craigslist and ebay guys selling the wrong year stuff a lot.

if the frame has a VIN, check the 10th letter.

H=87
J=88
K=89
L=90

And welcome to the site.

There's a lot of great info here just not as active as it once was.

Hopefully the facebook craze will end soon.