Yes good ones pull big money now. i know a guy who had a fully restored T160 with lots of new bits etc but then he never rode it and it sat in an air conditioned room. He eventually sold it last year for about $16K which was below his asking price but he could have got more because a day or later after he sold it another guy rang up wanting to buy it at his original asking price which was a few grand more, but he had to say sorry he had sold it. If you dont start off a real good one you can for ever be fixing up things on them though. Lots of anoying leaks start to appear. if the brakes have never been done then i can bet you would be up for master cylinders, caliper kits, hoses etc. I dont know of many 70's Triumphs getting around with the original master cylinders these days. i always end up fitting stainless steel ones to most. On the Tridents, especially an import, it will take some time to get them tuned and running properly here. carbies should be removed and have the slides balanced properly and tuned to the fuel here. Also check for slide wear which is common on high milage bikes. Most people will need to go to a colder plug aswell, especially for town/city riding. i also recommend upgrading the rocker box base gaskets to solid copper gaskets (also for good for Triumph twins too) They are much better than the original or common type gaskets availble in the kits you by. All Tridents i do i put solid copper gaskets on. I like the triple sound, but would much prefer an XS750. i restored one of those once and fell in love with it. Much more refined, maintenace free etc compared to the Trident.
