No finish on necks isn't a good idea as there's nothing to stop them being instantly being affected by changes in humidity, including sweat/moisture from your hands. So you'll get a lot of neck movement as a result and you'll have to constantly adjust the truss rods to compensate. Especially as the kit necks won't use the best quality quarter-sawn timber for the necks.
The EVH has a satin polyurethane finished neck, so you could get a can of that and apply a couple of coats. Or you could use a few applications of TruOil.
I'm assuming the necks are maple. That's a very hard wood with microscopic pores, so it doesn't absorb much of any finish, so two or three applications should be all you need. I'd also thin the TruOil down with turpentine to about 50:50 to get smoother, thinner, coats on the neck. It may wear off over time, but it's easy to apply another coat or two when it looks very worn. Rubbing it down with 0000 wire wool or P2500 sandpaper once it's cured for a month or so will give a satin feel to it.
Last edited by Simon Barden; 08-07-2020 at 07:22 PM.