We don't know. If the bones are "adapting" to a lower gravity, and stop getting weaker at some point, then it may be OK. If the bones are losing strength all the time, then it may not be.
And, of course, bones are not monolithic atomic objects but complex living things. Different parts of them may be described by either of those two cases, or others.
And, of course, bones are not monolithic atomic objects but complex living things. Different parts of them may be described by either of those two cases, or others.