[Arran]

I think that $3700 is definately at the higher end of the price range for a 37 or even a 38-690, quite frankly I have never heard of one selling for that much although the Estes Auction may have. Compared to the 37 and 38-116 they are rare in that production was in the lower four digits compared to five digits with the 116s, for a top of the line high tube count set they seem to have had rather high production numbers and apparently also had a high survival rate. There are rarer sets in both the 1937 and 1937 Philco line, but that doesn't make them more desirable just more interesting.
To be brutally honest, I think if someone has to charge $1500 to electrically restore even one of these they they either don't know what they are doing or they are shaking down their customers. In all honesty unless they are doing something like fabricating a new power supply/amplifier chassis from scratch where is the $1500 going?
The same goes with the refinishing aspect, unless the cabinet has to be virtually rebuilt form the ground up, in fact most shops would go out of business charging such prices for a simple refinishing job. When it comes right down to it even a -690 cabinet is just a box, a larger box but a box none the less, the value of the actual radio really does not come into play here with restoration costs, it's straight labor and materials.
Regards
Arran