Just as an FYI that may affect you since your a Gilson/wards guy. while I am not sure when, those bikes did sometimes come with Taiwan made imposters. I had found that in a batch of shocks I had bought in the past. Also, while they look nearly the same and are interchangeable, there are differences in lowers over lengths usually between spring/dustcover styles. So if your trying to match something up you may want to get a true measurement with exact measuring points listed up you may end up lopsided.
This link should take you direct to the posting I did when noting the copy shocks, if it just takes you to the start of the thread is post #153 found on page 16.
https://www.oldminibikes.com/forum/mini-bike-discussion/9933-sebac-shocks-16.html#post1062177
Also the last post I did after that one shows some more of the differences on the Sebac full dustcover/fat springs too. Those usually are what the gilson/allis/wards used from what I have seen.
If you come up with some true measurements of the lower you have I will see what I have in my parts bin, I have some spares.