Not at all true. However, your department will have to install things like properly certified safes into your house. This may mean bolting things into your concrete basement, etc.
For all practical purposes it is true that classified work will not be done at home for a long period of time -- because doing meaningful classified work over a long period of time requires connectivity to a classified network, which requires a bit of infrastructure and the relevant accrediting authority has stringent requirements for this kind of thing.
I've personally participated in the accreditation of on-site SIPRNET (which operated by DISA at SECRET//NOFORN) enclaves and it is an expensive process that your company will not pay to have done at your house.
In addition, there would need to be daily audits of the security records for things like vaults, rated security room (even without open storage), and a vault for the Type 1 encryption device (which needs its crypto keys updated regularly) -- at the least -- which connects your (or really DISA's leased line) to the peer.
