That's just the way the auto industry operates and your car is indeed a '93. Mine was also manufactured in 1992. The small printed manual that came in the trunk compartment is the same as the larger size FSM, and I don't think anyone has scanned and posted the '93 manual in pdf form, but the '94 manual might be close enough.
People on this forum are VERY helpful, fairly knowledgeable, can point you in some good/right directions and all J30s suffer from a fairly common set of problems. Unfortunately and too often, only the problems and not their exact solutions are posted.
The VG30DE engine is basically the same as the one used in the '90-'96 Nissan 300ZX.
1972 Datsun 240Z - non op since 1986
1987 Toyota MR2 - 199K+ and counting
1993 Infiniti J30t - 174K+ and counting
1997 Ford 150 - 87K and counting
2003 Saturn VUE - 112K and counting