Lowered my 79, now it's leaking from the trans tailshaft

[Scott76]

5/7 mcgauhys static drop. 454/350 driveline.

I've been building the truck for a few months, it's been on jack stands in my garage almost the entire time. I'm just about ready for paint and put the truck back on the ground, and it's leaking pretty bad from the trans tailshaft. It does not leak when on the stands. I'm thinking I stupidly put the drop blocks for the flip in backwards, but I can't remember which direction I put them in (hole facing front or rear) since I did the drop almost 2 months ago. I really don't wanna pull it apart and do it again, but that's the only scenario that makes sense to me. Could it be that jacking it up and having the axle moving around could have damaged the output seal and it may have a nick in it that only gets exposed /leaks when it's on the ground? If I put the lowering blocks in backwards would it be very obvious?

I know I can pull it apart and check it, but I'd obviously rather not if I don't have to. Which direction should the hole in the lowering block for the spring pack face? Front or rear?