Hi Larry,
You will likely be able to find a used tubular internal trunk lid (boot lid) support without too much trouble.
The reason I think it will be relatively easy to find is that the trunk lid itself tends to rust from the bottom/rear edge up and is much more susceptible to rust than the separate internal frame. The lid is much more vulnerable to accident damage, as well. So, a usable frame might be found on an unusable trunk lid. Even a slightly bent or tweaked support frame is relatively easy to straighten.
So, just be patient and you will find one in time. Check with anyone handling used TR parts.
www.triumphsonly.com probably has several to choose, but likely at 2X the price you might find it elsewhere. Post a wanted ad here in the BCF classifieds, and maybe alco on
www.craigslist.com if they are in your area. Look in your local area for any wrecking yards specializing in LBCs. Look on eBay for anyone parting out a TR4/4A/250.
I believe there are two slightly different versions of the tubular trunk lid frame. The very early one was fitted with a solid prop rod (similar to the one under the hood) and I think has an extra hole or two. The later sliding/telescoping prop rod version is much more common and what you need for your car. Still, there wouldn't be much difference with either type and an early one could be used.
Based upon the serial number, I'm pretty sure your hood should have the longer power bulge and the flats for the rubber bumpers at the rear corners.
I've never seen a pdf of the parts manual. Instead I've got the printed parts manuals. It's useful to have TR3 and TR4A, too, since many parts are shared, or to distinguish what's definitely incorrect for the car. Some vendors will happily sell you a TR4A item and just hope you don't know the difference... that's probably why they created their own parts numbers, instead of just using the established factory parts numbers which would make substitution obvious. TRF and Rimmer Bros. use the original numbers. To some degree, so do Revington TR, Ted Schumacher and British Parts Northwest.
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