Good. How did you track it down?
I think your trailer is just like mine and is a eagerbeaver ap10. Not sure why it would be an ap10L. Are your wheels the house trailer type (8x14.5) where the rim is held to the central hub with 5 bolts?
AP10Ls made in the early 90’s through about 2005. Traditional AP10s had leaf spring suspensions and spoke wheels (14.5 tires). We did make some transition period AP10s (leaf spring suspension) with 865 hubs (8 bolt on 6.5” dia center). They were still sold as Model as AP10 and the GVWR and GAWR did not change.
The AP10Ls all had 865 hubs and Torflex Suspension. It is still only rated at 12,800 GVWR, just like an AP10. The big difference with the AP10L is the GAWR. AP10L had about a 400 Lb per axle higher GAWR. This means you can put more weight on the tires & distribute less to the tow vehicle the hitch and still achieve the 12,800 GVWR.
In order to get you a s/n, it should be shown on the title, Bill of Sale or old registration. Failing any of these not being available, it is possible that there is a hidden number stamped on the underside of the trailer. These numbers normally are on the curb side and stamped in the bottom of the main beam or one of the cross members. If you can find this number, we can possibly trace it back through our records and provide you with a s/n and other pertinent information.