I am pretty sure it is a Mad River Traveler. It could conceivably be a Fingerling but I believe that boat was made by MRC for only one year (1984). The Traveler was a somewhat cut down version of the Screamer, which was a solo downriver racing hull designed by Jim Henry in 1973. I believe that the Fingerling was from the Screamer mold as well and cut down a bit further. The Screamer was sold by MRC from 1975-1985, and then the redesigned Traveler was sold from 1986-1990. That boat was made in March of 1988. The “K” appended to the end of the 12 character HIN confirms that it is Kevlar. But 58 lbs would be very high for a stock Kevlar Traveler which should weigh closer to 47-49 lbs. In this case, a thwart that would have been positioned in front of the solo sliding seat has been removed, and two wood-frame cane seats have been added, which would add a few pounds, but probably less than 10.
If you are considering buying this boat, two considerations should be foremost in your mind. First carefully examine all wood on the seats, thwarts, deck plates and gunwales. It is clear that the very front of the front deck plate has rotted out, and the gunwales certainly look to be in need of attention. If the gunwales are sound, perhaps all that is needed is a good sanding and oiling, but I would carefully check for dry rot of the gunwales, undersides of the deck plates, and undersides of the thwart and seat hangers where they meet the gunwales. If the boat needs to be rerailed, or needs attention to the trim above and beyond repairing the front deck plate and refinishing the gunwales, I think the asking price is too high.
The second consideration is how do you plan to use this canoe? As a solo canoe, it is very large. If you are a big paddler planning to use it for tripping with a substantial load, that may be good. If you are average-sized and plan to paddle it solo on day trips, it is probably too much canoe. It can be paddled tandem by a reasonably light tandem team, but it requires at least a moderate degree of skill to use it that way, because it is significantly narrower at the water line (about 29") than most tandem canoes. It could conceivably be used to paddle from the center seat with two smallish children sitting on the bow and stern seats, providing they don’t move around too much.
I have owned a Traveler since 1990. Although I have not paddled it for years, I did use it extensively on lakes and easy rivers and usually had one of my daughters sitting in a low folding chair just in front of me as I paddled it with the center slider all the way back. The boat is reasonably fast but straight-keeled so it is reluctant to turn unless you know what you are doing.
Here are a couple of threads discussing the Screamer/Traveler that you can peruse and decide whether or not this boat would suit your needs: