lol, most people have trouble getting them off, not putting them back on
The 'former' is likely a dust cap removal tool, specific for Alko dust caps. I have one and they're incredibly useful.
It a cast ally tool, that fits over the dust cap, with an arm sticking out of it (that's a rubbish description, I know). You strike the arm and it pops the dust cap off, without damaging it.
The trouble with geting an Alko dust cap off, without one of these, is that you invariably damage the edge of the dust cap prising it off (using a screwdriver etc) and then, as it's no longer circular, it becomes a pita to put back on.
If yours still looks in pretty good shape then it's prob just a case of getting one half 'in' and then giving the other side a bloody good thump (on the turned edge).
lol, any of that any help whatsoever??!