They're exactly the same. The Spoon is my default choice but since Charge went pop the Maddison saddles are the place to go. A few others use the same design but these are the cheapest from what I've seen.
https://www.biketart.com/products/madison-flux-classic-saddle?variant=42485048574131&gad_source=1&gad_campaignid=22260246431&gbraid=0AAAAAD6KDBzJRe8e91WvB0kEBax9IIjC5&gclid=CjwKCAjw56DBBhAkEiwAaFsG-ozOfJZpLifsaKOKZAVXO1s_sudLe3R2TfiII2-_a3KW3_8jwcbWFBoCvs0QAvD_BwE
Hard to beat these imo.
Not at all mate. You are correct but Shimano used to release the next years group set mid to late the previous year so the 89 built frames were often built with '1990' kit.
Another example would be the 1992 MBUK Summer Special having a 1993 M560 LX equipped Clockwork as a prize. As Orange...
Not to derail the thread but most multi link suspension is based on the Horst link which dates back to the 80's! Modern shocks make virtually any platform work. Any way, back to the 5.....
Ultimately they were properly built back then and have little to go wrong so should be a safe bet.