On my previous BF the strut was on the top of the door, but on this one it is on the bottom so not sure if same length.
Sticker on mine says "Signature Series Gas Springs" made by "Newport Engineering Associates Inc".....
www.mygassprings.comTheir website shows a whole bunch of models...mine is: part# SX200P...12" closed/ 20" open.
Hope this helps
Bill..
2017 Bigfoot 10.4 camper...2016 GMC 3500 4x4 Xcab Duramax Dually...