First, Welcome to LTG!
The D-46 is an interesting guitar, made for a short period in the first half of the 80s. AFAIK, it is the only Guild acoustic made with ash back and sides. It's basically a dreadnaught (think D-40 or D-50) with ash back and sides and an ash neck. The ash gives it a very striking "striped" appearance... Some like it, some don't (I do).
The early production D-46s often have a rosewood centerpiece in the back... making them (AFAIK) the only Guild acoustics with 3 piece backs. This was probably done to use ash pieces that were too small for the complete back, rather than for acoustic reasons. I don't know that I have seen a D-46 with the rosewood centerpiece later than mid-'81.
Tonewise, my D-46 has a rich, balanced tone, with sparkling trebles, strong mids, and a good solid bass. Sort of in between mahogany and rosewood... richer sounding with stronger bass than my mahogany D-35, but brighter and with more "jangle" and more balanced than my rosewood D-50. I'll add that mine is QUITE loud... one of my loudest. I would think it would be a good alternative to mahogany for bluegrass leads (but I am not a bluegrass player).
It's not what you would call rare... you will see half a dozen show up for sale on eBay in a year. Depending on condition, they might sell anywhere from $600-1100.