The very early Olds horns didn't have model didn't have model designations. They were sometimes marked "F.E. Olds" and sometimes "The Olds." They were generally referred to by their features, like "Self Balancing" to refer to one with a tuning slide in the bell. Models with Tuning in Slide were generally identified by numbers stamped into the bottom of the slide connector. LP means "Low Pitch" and is generally more desirable than HP, which is "High Pitch." Low Pitch horns are generally able to play in modern ensembles. You'll have a designation of bore size, which will run S M or L. Finally, there will be a designation of bell size--somewhere between 6" and 8". Some had counterweights shaped like a bear, some like a bat's wing, some had none. The bear adds the most value to the horn. Some had fluted slides (ridges on the inners) and some didn't. The small bores aren't worth much. Some people like the large bore and small bell combination, but for my money the best you can do is an LP/L/8/Bear CW/Ridged slide. And that's what I play!
If you're talking about this one on Ebay:
it's worth what someone is willing to bid for it. I was going to bid around $25 and cut it down into a TIS alto. The condition of the horn makes a lot of difference in the value, and this one looks like it's been gracing the wall of a TGIFridays for awhile and chances are the inner stockings are shot. It's also generally not a good idea to buy from someone who knows nothing about horns, since they tend to miss detail which can have a strong effect on the horn's playing characteristics.