I do not know what the #1, is but metric bolts are identified as follows:

8mm (major diameter of threaded area, not head size or root of thread), 1.0 (thread pitch, crest to crest in mm) You will find thread pitchs of .5 (very fine), .75 (fine), 1.0 (average), 1.5 (medium), 1.75 (coarse).

American standards are identified by TPI (threads per inch), ie 5/16-18 (5/16 diameter X 18 threads per inch.

If in doubt do a google search on metric hardware.

Michael

EDIT:
Length does not include the head thickness, the only exception is with flathead hardware, flatheads are measured by total length.