While going through my MUL I got an interesting stat.
There are about 2623 total mechs in the BTU. Not including LAMs or IndustrialMechs.
However, there are 482 actual models, and of those, 20 are 'IIC' models, and 23 have the words ' II' in them, many of which are just a rename of the base model. There are also I think 3 FrankenMechs.
So basically, the BTU has about 450 mechs, with over 2100 variants! 10 of the total don't have a record sheet or enough data to reconstruct it. I have found 87 mechs missing from the official MUL, though many of those (49) are the base model (empty) omnimechs. 26 of them there is some issue with the record sheet and data where the mech cannot be reconstructed legally (often as there is no RS), and 16 have armor rounding issues.
I finished all the WS and many DS, so there are only 61 elements left, mostly dropships from TRO3057 Revised. I was going to go through and ensure all my page numbers are right, but after recent events I don't care enough to.
I should have something to view soon, but need to make a web page for it, and it'll be a model ugly web page :)