NOS Shure V15 type III cartridge opinions


I know this sounds crazy but going thru boxes stored in closet for the past 40 years and found one of these I had purchased in 78 as a spare and never used. My question is should I open it up and give it a spin on my vintage TT or keep it to replace my in use cartridge until it goes south or open it install to see what happens? Wished I had another headshell. I read this was the best mm cartridge build, great all around sound and unsurpassed tracking. 
Or put on market? I'm leaning toward trying it out but then again?
128x128gillatgh
Thanks Dave that helps a lot. I noticed you mentioned a yellow pull out elliptical stylus. The label on the box says it's elliptical but the stylus is a pull out black  and the body is silver. Do you know if stylus colors changed somewhere along the way?
I'm becoming more familiar with it thru reading and am more than likely going to try it. I do blues and rock so this may be right up my alley. If it pleases I'll hold onto it

Black pull body (VN35e) would be right for the elliptical on the Type III. Operating from memory on that one as it was been a long time since I had the elliptical stylus. Sorry bout that.

Enjoy your cartridge!

Dave
I had the elliptical stylus and later replaced it with - I think - the MR (but it could haven been the hyper elliptical). The update was a real improvement with a sweeter and more detailed sound. It was an excellent cartridge, but required precisely matched capacitive loading. At the time, Quad made special inputs boards for them, to match loading and output level. Tracking even at low pressure was exemplary, frequency response (if loaded correctly) was very flat, and distortion was low. However, the expert opinion (including that of Shure itself) seems to be that these days no original stylus assembly can still be in good working order - it will have dried out.
Use it!  The VI iii is an excellent cartridge. My Son has one and uses it daily. Wonderful dynamic and well balanced. 

N.