mang rudy made/"assembled" one for me back in the early 90s. i met him personally -- muntik pa akong nakagat ng aso sa may bahay nila. i gave him a body, a neck that needed refretting, EMG pick-ups, a floyd rose trem, and the rest of the hardware. he fixed the neck, assembled/installed everything else, repainted the body, etc. the result was a really good guitar. it's now with my cousin.
was this guitar solid proof of mang rudy's skills as a luthier? maybe not... since he didn't build the guitar from scratch. was this guitar solid proof of mang rudy's skills in general? probably so since it still needed someone with knowledge to refret a neck, make sure things are aligned, etc.
all: take whatever you want to take from this example, but like all examples, this represents a data point... nothing conclusive, and it's up to you to decide whether or not this data point plus other data points make a trend. as for me, i cannot listen to one horror story and conclude that everything else the guy made or touched is bad.