Identify Rear Axle?

I have a Toyota pickup rear end (2WD) which is not in a vehicle and I'm
trying to identify it as a 7.5" or 8" ring gear. I believe it to be an '84
model. From what I've read, most 2WD models had the 7.5" ring gear, but some
may have an 8" even though 2WD. Here's what I know about it. The axles have
27 splines, and there's 23 splines on the pinion. The ring gear actually
measures approximately 7.5" O.D., but the case / housing looks exactly like
the pictures I've seen of the 8" 4WD cases. I can post bearing numbers /
sizes if that would help. Are there any other specific identifying
characteristics that would help identify it? Anyone know what I've got here?

Bob