Found the Fox oil volume chart, but their proper service docs are damn near impossible to find now.. F100s changed from Open Bath to FiT cartridge dampers in 2010; the large oil volume indicates you'll have an '09 or earlier fork.
You don't have to drop the damper guts if doing a lower service, but given you'll be draining all the oil when you drop the lower off, it's not much of an extra step to give the damper assembly a clean while you're at it. The air side can be untouched. 10W oil is normally a bit on the heavy side for a damper bath, but given in this instance the bath is both the damper fluid plus lubricant for the stanchions, it needs a bit more body to stay up in the bushings & not drain straight back into the puddle at the base of the leg, but not so thick it can't flow through the damper properly, so Fox specify it as a trade off.
One word of warning: The newer flangeless dust wipers that Fox have been using for the last few years (and fully compatible with older forks) are absolute bastards of things to get in. Unlike the older ones which were mostly rubbery plastic things which had a decent bit of flexibility to wriggle in place, these new things are predominantly brass (I think, or maybe a brass-coloured anodized aluminium) with a thin rubberised coating, and have basically nospringiness to wriggle with. If they go wonky when trying to seat, they'll bend and then they're fucked and won't go in at all.You really need to use a proper wiper press tool the right size to have a decent hope of getting them in, but even that can go awry sometimes.