Interesting, mine appear to have identical parts, but the head is made differently. Instead of everything going in the front of the body, the head unscrews just like the back end. The lens drops into the head first, the LED board next, then a ground-return ring screws in and tightens everything against the front of the head. The big spring goes in last, compressed between the screw-in ring and the body of the flashlight.
Turns out that ground-return ring is what was giving my lights grief, not the switches. Found that when I was messing with the LiFePO4 batteries yesterday. On mine that ground-return ring had loosened and was making intermittent contact with the LED board. My switches "failed" because I was pushing too hard (and frequently) trying to "get them to work"!
Once I tightened that ring, put the switches back together in the tail end, and tried them again - still work fine every time. Of course I have to be careful - just a bit too much pressure and the switch pops out of the housing and I have to put it back together.
My flashlights are store-branded, bought at Office Depot. Couldn't find them on their website, they are (were) just in a big bin by the registers. They were a bit more than $1 though, maybe $3?