Not a dumb question, I could clearly hear it coming off my 'puter screen.
Yes, it is something that needs to be measured, and it is different with each type of bullet you are using. Some rifles, I have some myself, have throats that are far longer than you'd expect, but it doesn't seem to pose any problems when other good loading techniques are used for very good ammunition.
To measure the simple way, take a case and cut 2 slots in the neck opposite each other, or indexed, they only need to be about 1mm (.040") wide each. Place the bullet you wish to use, carefully chamber it, cock and uncock the bolt a couple times, then carefully remove the round from the rifle. If your rifle has a plunger ejector, you will need to keep finger pressure on the case to stop it from dragging on the chamber/action wall, this may alter the measurement if not done. Re-do this several times and record the measurements, an average of 10 measurements should give you a measurement to work off. You will need to size the neck between tries. There are 2 measurements that can be used, COAL (head to bullet tip length), and CTOL (head to bullet ogive length). The latter is the more accurate of the 2, byt when measuring for the magazine length, I always measure COAL and give .010"-.030" of play in the magazine. I only use ogive measurement in my target/long range rigs that are single loaded mostly.