Man, you don't hear about people steeling a fifth wheel very often. What do you do with it? Can't hide it very good unless it's in the boonies. Wonder if they have chop shops for RV's. Sorry that happened to you, and glad you have a replacement now.
If you haven't noticed any excessive movement in the pin box while towing, or cracks in the fiberglass, I think you're fine. I too worry a LOT, and put a trail air pin box on ours to try and minize the shock on that portion of the frame, since that seems to be where some have cracked in the past. I'm gunshy on the Lippert frame, but haven't had any issues to justify worrying. Not sure how much you've used it, but just for cheap insurance, get it loaded and put it on the scales to make sure your within the GVRW of the fifth wheel. The vinyl filler strip can be bought at just about any camping place or RV dealer in a roll.
John and Rebecca Dickson
Emma-7 / Little John-5 / Iva-1
Full Timing Again, Rev B
2013 Ford F-350 Lariat CC LB PSD
2015 SOB TT - With OC's Awning Poles (#8)
At least in Heaven, RVs will be perfect, and I won't have to keep fixing them.