if that is your chassis then it is a 2/2a
if it had been a W shaped piece of steel welded on rather than those two plates with bolt holes in them then we'd be looking at a S3 chassis
folks get caught out and buy a 2/2a with supposed bulkhead swaps occaisionally (unscrupulous sellers) if they're not familiar with the differences around the Series motors
i've even seen one Series that was supposed to be a 2a that actually was a cobbled together assembly of parts, it was still on leaf springs but the chassis was from two different models cut and cobbled together (military rear half, civilian front half and a foot or so of homemade box section joining the two bits together in each chassis rail), it had the front crossmember cut out and moved forward to allow fitting of powersteering, a pair of disco axles under it, a 200tdi motor, 90" bonnet and grill, S3 bulkhead, S3 tub....
that motor was sold to a mate as a 2a by a well known dealer in secondhand landrovers without full disclosure of what was being offered
then to cap it all off, being as the chassis had been cobbled together it crabbed really badly
i dread to think what would have happened if he'd been in a serious prang with it