I don't recognise the second plant either, but it is stil quite young. The spines do develop as the plant ages, in most species. There are some in which the radial sipnes seem to drop off, such as M. sempervivi, and others in which the spines grow much stronger and longer and sometimes more numerous as well, as the plant ages. This last sort are by far in the majority.
You don't get the major change in spination that happens with Coryphantha for example, though.