another furnace age question

This furnace had the name tag removed
mfg # CUGE075AG01
ser # L912475960

Thanks
Allan

Just a guess,
75,000 input BTU
1991

Was it a Keeprite that is owned by International Comfort products , L=louisville plant, 91 is year and 24 is week, Inter City Gas (I.C.G.) I think used this code also, looks like 75,ooo BTU

I figured it was probably a 91
thanks for your help

Allan