The silicone should not be a problem unless it is leaking already. I have a 66 that is 18 years old and still going strong also an assortment of the old 50's & 60's MetaFrame Aquariums............ never had a leak in any tank I have owned (knock on wood)
I think the major consideration is........... has the tank has been placed on a level surface and has not been torqued on an uneven surface?
Cheers,
Vic[veng68]