Yes, in fact the military has a system in place to make sure that they only that they only use alternate suppliers and on Anthropic AI, They do this by placing a designation on Anthropic AI that it is a risk to the supply chain, which forces purchasers to use other suppliers.
I don't think this is how preferred suppliers have typically worked through the supply chain risk considering the US has definitely had preferred suppliers before and has not historically used this against a US company that was not on the list and the power of such a designation extends far past the military into all parts of the government. I'm pretty sure this has more traditionally been relegated to simple requirements or specifications.