Or, if you prefer, I can dig through some old posts on this list, and tell you the depths of the cuts for XX2247. It has been widely discussed a few years back.
On Mon, 25 Apr 2011, Ethan Dicks wrote:
1 - 0.0155" 2 - 0.0310" 3 - 0.0465" 4 - 0.0620" 5 - 0.0775" 6 - 0.093" 7 - 0.1085" 8 - 0.1240" Meaning that the XX2247 key would have depths (in the order you describe) of 5-1-7-3-7-5-7
Given the "5-1-7-3-7-5-7", a locksmith with a tubular "code cutter" can make a key. Most tubular key machines can be used to "code-cut"
But, YES, a prior owner might have removed the lock at some point, and deliberately rekeyed it to different cuts than it came from DEC with. Not likely, but possible, particularly in some college CS departments, where lots of students have XX2247 keys.
