I have no doubt they can make a model of a lower.I have made far more complex parts than a lower.I have played with a running gearset,the gears and shafts they ran on were all done in one shot.Have fun,maybe they have developed far better materials.
In my experience,dated as it is,the parts created just did not have engineering properties anything close to ..say Lexan,or graphite filled nylon,etc.They were useful for engineers to hold the vision in their hand,check assemblies,etc.They were great for the moldmaker to look at designing a mold.(That is an interesting excersize off 2d blueprints of a part drawing.)Package designers can use the parts,and ,cosmetically finished,Marketing can take ad pix,etc.We never got anything that was good for functional parts.They were stronger than Doritos,but not nearly as strong as the cheapest of moldable thermoplastics.
They may offer a service of converting a 2d drawing to a virtual solid 3d model,but I suspect the process is not done with 2d drawings.
Softwares like Pro-Engineer and Solidworks can make the sort of database you will need to work with.
Good luck,keep us posted.