Confession time. Back when I was a 16 year old aspiring mechanic, I bought my first Mustang, a 67 fastback that I built in my gaage. Being the stupid ass kid I was,- I pulled off the A/C system because that "dragged HP" and all my friends were ripping out their AC to make their cars "faster". The car was black on black and in the heat of summer in NJ with long tube headers and sidepipes ( yes it was the 70's) , that car would get hotter than a frying pan. Drove that car for almost 3 years with no A/C but as a teenager who cared. Got me more girls and into more trouble than I will ever admit
However, after that experience, every single car after that is a DD had A/C.
Before I bought this convert last year, I looked at over 30 and maybe 2 had working a/c. Half had them deleted or pieces of the system missing. The rest .............does this sound familiar?....................
"Just needs a charge" 
So when you ask, then why haven't paid the $100 to charge it then so you could sell the car for more money? Then the stories begin.
Oh, you don't need A/C on a convert
I never used the A/C
I don't have the time
It was like then when I bought it
That's when I tell them it will most likely need a new receiver/dryer, hoses, converted to 134 etc, and you are looking at anywhere from $500-1000 to fix and that is coming off the price.
That's why I paid a little more for the one I have, knowing it was all original, 42000 miles and everything worked.