I have an Uggy that was Mod/Full when I bought it. It actually threw patterns closer to full and full.
I opened it to CylMod, but the 'smith actually went to Cyl/Ic. I was a little ticked off, but, have used it for pheasants, grouse, sporting clays, skeet, and a few pokes at my local duck tower, and a not bad round of trap a few weeks ago.. It works fine the way it is.
I wouldn't worry much about value on an Uggy, especially a 12 gauge Uggy. Most people I know would spend the money to have the chokes opened anyway, assuming Mod/Full.
The guys with tubes seem to put a couple in, and then forget they are there. Nice to be able to change, but, few guys actually do.

Good Luck.

Best,
Ted