For hot caustic bluing? Sure, if you can find a supplier who will sell to you.
If you plan on mixing your own, you may find it difficult to buy the potassium or sodium nitrate needed. There are formulas that use ammonium nitrate; it, too can be problematic to purchase.
Do you have the tanks and burners?
It is easier to get set up for hot water bluing. The chemicals can be purchased ready to go.