To the best of my knowledge Johnson was using the leather-wrapped wood grip until 1926.
I believe when the A-35 came out in 1927 that they switched to rubber grips. I cannot tell you if the Johnson name was on it or not, but I honestly don't think that showed up until sometime in the 1930's.
FWIW I've seen many 1926 vintage A-25's and P-30's with the leather-wrapped grips, but never anything later.
Hope it helps.
Best, PM T2