I bought a Cannon brace after have RB's for a year. Much happier with the Cannon, and I feel its the first thing to do with your suspension if you have an earlier model like me. IMO of courseShort answer is no.
The factory front brace started in 94 if I remember correctly but the threads, or captive nuts, are not present on cars before that. Just about any aftermarket offering will make a noticeable change in steering feel on your 90. I have the Racing Beat front brace on my 92 and recommend it, although there are cheaper alternatives, I prefer the cast construction and backing plates that the bolts go through.
The rear brace from 92+ can be added if you weld the needed tabs into place, otherwise RB makes an almost pointless rear brace, and FM sells the much sturdier, and more expensive, Cannon rear brace. There are other rear braces but I am not familiar with them enough to say anything good or bad.