Ah, yes..... Well spotted. The L designation, such as L2A3 or L34 was often - but NOT always - stamped after the commercial Mk type designation to indicate the gun was in fact identical to the UKMilitary L2 or L34 gun and as a result, the spare parts, and what you were getting/buying were one and the same. It also informed UK Armourers where ordnance resources were pooled, such as Malaya etc, that a 'foreign' gun that came through was a big standard L2 - or L34.
The miscellaneous instructions EMER did mention that in operational theatres where Ordnance stocks came from pooled resources, Armourers and quartermasters should be aware that gun serial numbers would not always conform to the accepted standard. We did see quite a few RNZN, New ZealandNavy, marked commercial L2A3's from the Naval dockyards at Sembawang