There was one reply by Yasashii Arbaito which I never did see so I wasn't able to confirm their guess at the ages. I will do so now towards the end on this post. Sorry for the delay.
You can see the previous messages at this link: http://www.tinyurl.com/z3vd
The wall oven looks to have been made the 49th week of 1995, the "94" in the serial number has nothing to do with its age.
The cooktop looks to have been made the 25th week of 1996 but the copyright date on the manual is a good indication as is the copyright found on many appliance's wiring diagram. At least you know it couldn't have been made previous to that date.
I don't have date code references for older KitchenAid products but I would assume with you it could possibly be a 1992 model.
All in all, not too old for appliances. Again, sorry for the tardy reply.
Dan O. - Appliance411.com http://ng.Appliance411.com/?ref411=Whirlpool+appliances