Do your research. An 01 license is dealer/ gunsmith, 07 is firearm manufacturer. There are all types of ins and outs on what you can and cannot do with either license, determined by the attitude of the officer auditing your operation. I guarantee each officer will have his own interpretation of the rules. An 07 license also opens the door to ITAR rules. I operated a Gunsmith shop for 40 years with an 01 license only. I “built” a few AR’s along the way, always on the customers stripped lower. The last interpretation of the law was, if you supply the lower, you are building a rifle. If you put parts into a customers lower, you are repairing it.
Please don’t go strictly on my experience, talk with your local ATF office. Like I said, every officer seems to read the laws differently.