no... no, just because a 4mm allen key fits the head of the bolt doesn't mean that it's going to have 4mm threads or whatever.how so? a 1/4" bolt is a 1/4" bolt. 4mm is 4mm 5is 5 and so on
Lets talk about a simple wood screw. I can go to home depot and get a 3 inch wood screw with a head that will be one of the following: philips, flat head, torque driver, and so on. There are dozens of options. I can also get the same driving option for a 2 inch wood screw or #6 bolt or #5, #7 and so on...
Also the thread pitch will be different on each type of bolt along with thickness of the bolt and there are just a ton of variables that can be interchanged. Now typically the driver for said bolt or screw will correspond to a general size but that size will have a large range as will the # of threads and also it's rating for strength. All important things to consider when selecting bolts for any part of a bike.