Artillery was the least of the Red Army's problems in 1941. The Red Army had 117,600 guns and mortars when Barbarossa began, less than half of which was with their field forces. Most of it was in reserve. Glantz, Stumbling Colossus, Chapter 6.
The USSR produced 53,600 guns and mortars in 1941. In 1942 they produced 287,000. Glantz, When Titans Clashed, Table R.
Those are really nice numbers.
I hope, you know, how the su counted "Artillery tubes".
I will confirm your suspicion: yes, they indeed counted EVERYTHING, including 50 and 82mm mortars, light FLAK, AT-guns. Look at the numbers for FIELD ARTILLERY, and the numbers wouldn't look so nice anymore.
but lets see what this site thinks about it:
http://www.armchairgeneral.com/rkkaww2/weapons.htm
7,62 M02 and M02/30: 4477
7,62 M33: unknown
7,62 F-22+F-22USV: 4211 (max, probably includes other types)
4,5" Vickers How: 211 (maximum)
12,2 M10/30: 5578
12,2 M09/37: 778
12,2 M38: 1667
15,2 M31: 101
6" Vickers How: 92
15,2 M09/30: 2611
15,2 M10/37: 99
15,2 M38: 1058
10,7 M05 gun: 88 (maximum)
10,7 M10/30 gun: 863
12,2 M31/37 gun: 1255
15,2 M10/30 gun: 137
15,2 M10/34 gun: unknown, but there were only 275 produced at all
15,2 M37: 3123
20,3 B-4: 727
other heavy/superheavy: around 200.
Sooo... instead of having a nice number of 117.600 we have only a not-so-nice for FIELD ARTILLERY of only 27.551. Bummer.