when a rear track wheel is built, is it dished dead center of the hub? or offset? i know nothing about how wheels are built so bare with me.

Offset...just a wee bit.

edit: Here's a how-to for dishing a rear track/single speed wheel: https://www.63xc.com/dennb/redish.htm

It depends entirely on what kind of hub you are building up. I don't know of any double fixed hubs that aren't no dish. Most single fixed hubs require dishing, but some don't.

ok, lets say i have a wheel laced to a miche rear hub as apposed to a DA hub, will there be a difference in chain line? the miche hub looks wider since there's only threads on one side.

There may be a marginal difference simply because it is a different manufacturer.

Read this: https://www.sheldonbrown.com/chainline.html#hubs

Whatever hub you use, the rim centerline must wind up centered between the locknuts (the nuts on the inside of the dropouts). The cog on the drive side of a fixed gear or single speed hub makes the distance between the drive side flange and the centerline shorter than the distance between the non-drive side flange and the centerline, so the specific hub's drive side and non-drive side flanges must be measured relative to the locknuts on each end of the axle to determine the amount of dish.

Here's a drawing of a track chain line from Campagnolo Catalog 16 that may help.

i noticed that when i had a rear wheel built(fix fix) that the wheel would fit and have good chainline one way, then when i flipped the wheel around that the chainline was really off! WTF?

Maybe someone mixed up the spacers? I imagine there should be a similar amount of spacers on either size.
You can fix that pretty easily. Move spacers around (thinner locknut on one side etc.) so that you get good chainline both ways. Then redish as necessary. (Edit: You sure you have a similar cog on either side?)

BTW, I would just put the damn wheel in the frame to see where the rim has to be... dish it so that it ends up in the middle of the frame. Or get/make a dishing tool. The position of the hub is totally irrelevant (apart from the fact that you should dial in the hub position on the axle before you go about dishing)

i think the guy that built my wheel should have took this into account

The hub is supposed to come from the factory with the same chainline on both sides, I imagine...
Maybe some people with the same hub will chime in... If you tell us what it is and maybe post a few snaps.

From the Sheldon Brown article I posted above:

""Adjustable" means that the hubs use conventional threaded axles, so you can increase the OLD spacing by removing the locknuts and adding spacer washers.
If you add equal thicknesses to both sides, the chainline is unaffected, since it's measured from the middle outward.

If you add more spacers to one side, you can change the chainline, but if you do this with a double-sided hub, you will render it unusable on one side or the other, since you'll be increasing the chainline on one side while decreasing it on the other."