Need help identifying an old pack.

So I've been backpacking with an old "camp trails" pack that was supposedly bought in the 80s (edit: 1985). Its a canvas(?) bag with an internal frame (unknown material). It looks like its around 45-50l. Here's some pictures: http://imgur.com/a/sli1k My best effort on google turns up one "vagabond" model which looks similar, but is nylon and seems slightly different. This pack also fits the bill, but is also nylon and has a different logo. Any ideas on what I'm carrying? I'm thinking about getting a new pack since this things is older than I am and want some more information so I can get something similar but lighter. Otherwise how can I measure the volume myself?