how do you tell what kind of plane you have?

[Bob_Belville]

I don't think you can beat an original M20D or M22

Yeah, some planes probably deserve to be rare. (There were only 33 Mustangs and 160 Masters built and the vast majority of the Ds were converted to D/C.) 

 

M20E had a good run before Mooney committed to the longer, heavier F/J (1200 were produced in the 1st 3 years alone -- '64-'66). ISTM there are usually fewer E than C, F/J listed for sale because the M20E is very desirable. Excellent performance, low operating, maintenance cost with manual gear, hand pump flaps...  

[1964-M20E]

You need to remove the access panel located just aft the left wing and look in the tail cone to determine if you have a male or female.