I just went thru this on my build. Yes there are two types, the smaller switch only that I used as I prefer a light to shine in my face to indicate oil issues, not any sort of gauge that you wont notice, so knowing the switch was pulling to ground until its got pressure you just wire it up with 12 thru the bulb to the oil switch and it will work fine.
The sender for the pressure gauge is bigger and costs 110 bucks or so from toyota or $80 or so from tridon and the like. Its also on a lot of other toytas of a similar era with gauges like that at the wreckers.