Without a photo it's difficult to be certain. But, it sounds like what you have is called a pair of blankets. Some trade blankets were manufactured and sold as a "pair" i.e.. 1 double, length wise blankets to be split into 2 individual blankets at a later date, by either a trader, store/factory owner or the end user. I have a 3 point "pair" made by Rob Stone that I love. Mainly it is perfect for folding in half when you make your bed roll so your feet don't have a chance to stick out. I don't know when the Big blanket Manufactures (HBC, Whitney) quit making them, but they do show up now and again. If that is what you have, that's a very good find.