I found out the same way. I had two barrel changes on the same day, and neither would work! I checked every 22 and 32 single six I have.
Blue or stainless made no difference:
OM and pre 1986 NM Single Six .22 barrels, and 1st year, 1984, thru part of 1985 .32 barrels are 20 tpi x .557", the shank at forcing cone is .430" (earliest .32 I have with this thread is # 650-01300, 1st year, 1984 and the latest is 650-06801, from 1985 with this thread size).
Post 1985 .22 barrels are 24 tpi x .622", with the old size shank of .430" (lowest I have is #261-18748 from 1986) and .32 barrels are also 24 tpi x .622", but with a shank of .486" (lowest I have is # 650-14117 from late 1985).
All the 32 Vaqueritos will have the larger thread.