I'll have to check my vin when I get home but mine has/had carpet, two piece door pannels, extra guages, etc. AND, before I painted it, had SR5 on the tailgate, bottom right corner IIRC. I have always assumed it IS a sr5 because of those things, guess we'll see what the vin says.
If it has the "D" I'll make sure to change that in my sig so I don't offend anyone!

 

My 81 has the D in the vin as well but has power steering, tilt, had full carpet, back wall carpet, 5 speed, tach, had ac, and the sr5 steering wheel. also has only 2 hooks on the bed...but who knows!

 

"but who knows" Thats the question Toyota might not even know?

As far as equipment/accessories on trucks now, if you dont have the original invoice everything could have been upgraded as newer models came out, not uncommon at all to add tags or steering wheel ect. not saying yours isn't orig. just saying could be in some cases...

Not sure but seem to remember some truck beds were different in same year? maybe some from japan and others made here? not sure so if someone knows????

 

My guess is it all went down to the sales at that time, maybe the buyer got a deluxe but the salesman sold a bunch of options on it which would actually make it a sr5 with the 5 speed and all, but not actually on the vin.