Good to see I am not the only one to spend time a, buying tiny saw blades and b, the time cutting one off, only to then find the tab!
I went thru this not too long ago and after fiddling with spring bars all too long one rotated and voile it was an old Omega bar with the pin jutting out. I read this whole post only to see recommended to look for them. I had already forgot about them as a possibility and was reading along to see your solution. Sheesh! Looks like I am doomed to recreate the wheel or in this case, fight what may be easily removable spring bars if I only remember to rotate and look for tab. Oh, the watch I did all this on only had one easy one. The other side still took firm yet careful deliberate digging till I distorted it enough to get the bracelet off. That much I do remember.
I started noticing the pin spring bars on a 105.003 with 7912 I bought at a gun show in late 90s for 450. Prior I was unaware of these "cool" spring bars and have saved everyone I ever took off a Speedy since and they are in my drawer of Omega bracelet bits. PIA that they are.
The pin spring bars are actually convenient when used in leather straps with a cutaway especially designed for them which secures the pin in position. Strapsco straps for example uses them.