Newer models have been fitted with a new type cocking lever, I dont know if there is any other visual check without stripping and looking? someone with far more experience than me can maybe answer this?

I have been told of the following way is to look at SN:

New Style Cocking Lever Was Fitted To Models:
.177 - SN:1892759 Onwards
.22 - SN:1899147 Onwards

might help someone else