how hot are the glow plugs supposed to get? should they be litterally "red" hot?

i pulled out my #1 injector and fired up the glow plugs for a full cycle(~30 sec till i herd the relay click off) , stuck my finger down there. seemed warm. so i fired them up for another full cycle.
it definately wasn't "red" hot but i was dumb enough to stick my pinky down there and get burnt, it definately got hot.

so should it have turned red after 1-2 full cycles?

called my repair shop they wont/cant test the starter, guess i'll head over to the "good MB shops" forum to try and find someone in d.c. metro area.