1967 shorty or long bed ?

[1971_CST_C10]

so I went out and jumped at this all original 1967 Shorty with great Patina and has all the roughness that goes with the patina so its not painted on.
I checked everything from holes in the floor to make sure buddy seats are original to the truck as well as the frame for any cutdowns and welded in plates which would confirm a long to short conversion even checked the frame ends for straight cuts and they have the original notches and such. she runs great as a 327 M204spd truck. now that a couple of weeks have gone by I got the GM docs from Oshawa Ontario and it shows she was a long bed or long box from birth ??
i thought I checked this out where all the tale tell signs were suppose to be inc vin numbers on frame and by the PS pump. The spidd shows the M20 and the vin but where the model number goes it got rubbed off from almost something being slid accross the spidd heavily so I cant make out the 109 or 107 numbers.
what did I miss ??
other than that she runs like a champ and all the underside was redone from exhaust to springs front and rea to brakes and steering etc.
Thanks for imput
Darren