In neutral input shaft spins counter shaft which turns 1st and all other gears, only the mainshaft is stationary (driveshaft not turning thus you are slowing 1st to match speed of mainshaft That is an Downshift.... In no case are you ever trying to speed up 1st for a shift.
If you need to see a trans apart to truly understand that dynamic I have them readily available for demo.
I think we should consider the engineers would not build a 1st gear syncro assembly that in essence does nothing according to the theory that 1/2 the locks are left out.
I can sow you an Alfetta 1st, GTV-6 1st which are just like a 105-115. I jumped to fast on the inclusion of the Milano( yes it is very different and prone to breaking)
As I said I use 2-5 readily on 1st. after someone changes to a good carrier with new syncro of course "it works good now" you just fixed it just as if they had a good original 1st carrier with new syncro etc.