My 90 has the standoffs drilled and tapped but a flat tappet. Still might be a good deal.
It's a great deal for a complete good running TBI 5.7. I used to sell them for $500 (or was it $600? yeah, $600.. known running, demonstrated) air cleaner to oil pan with accessories and had no shortage of demand, and this was 10 years ago.
Do keep in mind a certain amount of accessories aren't directly compatible with your '90. The TPS has a different connector, the throttle body itself likely will not have the stud to mount the TV cable to your 700R4/4L60 (assuming your '90 is a light duty automatic), the EGR solenoid and EGR valve may not be compatible, etc. etc.
Overall though the majority of it is directly swappable for a '90.
Richard