Thanks, even having "Timberline" to search was beneficial as the pictures in the ad didn't show the model name.
I did manage to find an old classified listing for an 8' (7'11"), which had a wet weight of 780kg. I'm not sure what to expect the weight difference to be given the 1'8" and slight equipment difference. I'd been hoping to find something in the 500-600kg dry weight range, so this one could possibly fall in that range. But finding some confirmation would be nice, as I suspect the owner isn't going to be of much help and I have no desire to drive 10 hours to find out it is significantly heavier than expected.
It looks like Security Rv Manufacturing was purchased in 2002 by what is now Modulux Designs and the RV line got axed in favour of modular homes and cabins.