That's either a Lowden (probably) or an Avalon (in the early days, basically the same guitar) and it looks just like Don's Avalon L-32. Which is a super nice guitar. That was a fun little number!!
On the "Life & Music of RT" box there's a killer solo live version of Genesis Hall. RT's voice is nowhere near as lovely as Sandy Denny's was but he puts a lotta verve into this particular performance.