Are all Al-Ko Safety hitchlocks the same?

RamblingSid

I am just about to trade in my old caravan.  It has an Al-ko AKS1300 stabiliser and is fitted with the plates for an Al-ko Safety hitchlock.  My new 'van has an AKS3400 stabiliser, which is already fitted with the mountings for the Safety.

My question is, does anyone know whether my old Safety will fit the new stabiliser hitch or will I have to buy another one?  Al-ko seem silent on the subject, but places like Towsure seem to sell the same device as compatible with all AKS stabilisers.