[Arran]

Take about $100 off and you may have the right price, $175 is just too much for one of those that is missing the knobs, in fact it's too much for just about any late 20s early 30s console. In the case of the Philco model 65 that was their bottom of the line chassis with six tubes as well, some apparently had the model 87 chassis, the total production for the highboy cabinet was over 87,000 with either chassis so I guess they aren't really that rare. Although the knobs are out there they are very specific to those early Philco sets from 1928-31 so you can't just slap a generic set in their place. If you really want it make them a lowball offer if they can't locate the knobs.
Regards
Arran