Can the tires be the same size front and rear 30 x 3 1/2 or 30 x 3 ?

yes,
Pretty common the have 30 X 3 1/2 on front and rear. The earlier cars had 30 X 3's on the front. never was a 30 X 3 on the rear.

As Robbie says, cars of the teens came with 30 x 31/2 in back and 30 x 3 in front. Lots of people "cheat" and use the larger size on both ends, often the later demountables which didn't come long until the twenties.

Canadian Ts came with 30x3.5 on all corners. When I put demountables wire wheels on my son's car, it was recommended I do the same by those citing historic practices.

John your 1924 should have 30x3.5 on both ends front and rear.
I've seen folks use 4 rear wheels on the early cars and change out the hubs for the front, but my opinion they look odd with big fat tires front and rear.
Best thing is you only have to buy one size tire and your spares fit front or rear.....