About the case & bezel thickness, Kelster did some PT vs Gen pic's:
Although its a old sub versus new sub, the gen (right) seems to have a slimmer bezel and case.
I myself was wondering the same thing, back in the days one could get the TWB with gen service crystal from MBW. Can it be the main difference is the new bezel assembly? If so, would the old TWB's accept the new bezel assembly?
I think their cheap because it is case+tube only, no dial, bezel, crown or crystal. Take these into account and you end up spending more then a 160xx case for 200bucks.
Care to share the symptom's of the problem?
If the clasp is not closing anymore you have got to bent ever so slightly the inner curve of the clasp (hope i make sense here).