Hi, That number dates from 1951-'52, and are the early design. They use a slightly different crankshaft primary drive sleeve, with a scroll edge. Over time whether by rationalisation, design, or substitution, early engines without a seal are found with a smooth edged drive sleeve, according to findings by Forum members, so any sleeve you have will fit.
Design and part applications for the drive sleeve, oil slinger and later oilseal are all covered extensively within previous forum posts. There is no difference in the basic crankcase castings for A7 or A10 variants.
The condition of the anti drain ball valve in the oilway between pump and timing side bush is often overlooked, as is the integrity, operation and oil tightness of the sump pick up pipe. Problems with either can only be fixed by splitting the cases, once more extensively covered on the Forum so plenty of information available to consider.
Cheers, Swarfy.