I'm assuming that you mean "add a blueprint to the player inventory", in which case, yes.
The command is, for example, something like "addspecial ship_bp Omen"
Use the various "list" commands to see what your options are.
"list specials" should give you the list of all available "special" items, which includes all of the blueprint packages, as well as the necessary key codes for ship/weapon/industry blueprints. (For example, in the above, I said "ship_bp", but that's going from memory and might not be quite right - use "list specials" to find the exact string needed. As with anything programming-related, precision is important, and trying to "addspecial ship-bp Omen" will just get you an error message.)
And "list ships" will give you all the ID strings of the various ships. Vanilla ships are usually just the ship name, but most mods use prefixes to help preserve uniqueness, so you might see a ship ID string of "ms_tartarus" when the actual ship's name is just "Tartarus". Also, as these strings aren't normally player-facing, people tend not to update them when ship or weapon names change during development; if you can't find what you're looking for, check the various .csv files to see if it exists with an id string that doesn't match its name.
Some specials - blueprints for individual ships or weapons or industries - need that third argument. Others, like the various blueprint packages, don't. I.E. "addspecial high_tech_package", with no third argument.
