All good advice given - that price seems in the ballpark.
I have seen VERY few of the Metralla 62's for sale anywhere.
The Model 23's I see going for 6-9,000.
Thankfully I have one of the M8's and very soon I may have her a big brother 250
The 4 speed 200 is a perfect little back road runner. Not crazy fast or even exceptionally quick off the line - but once she gets going you get from turn to turn plenty fast.
And the feel of the ride is really wonderful - very solid and responsive - and the sound ! almost the best part of the whole package.
The M23 is a little bigger size - and quicker and faster, but also a little less raw and salvage ( spanish wild )
The balls would be to turn the M8 into the RS version - see below. Used to be just a few dealer options and some head work, move the pegs - now you need to track down some hard to find parts as well - but still do-able.
The Kit America M23 is next to it in the pic.