According to Patrick Antique catalogue, the 235's with the 2-hole valve cover, were the very first full oil pressure engine and were the 1953 Power Glides.
The better way to state what I think you want to get across is that the first high-pressure 235 was the one used in the 1953 Powerglide engine. The valve cover on that 235 had the same 2-hole valve cover as used on all 215s and on all 1953 and earlier 235s.
