"Battery is known good" - By WHAT method? If it's just you saying it's good, then no, it's not "known" at all. Has it passed a load test? I always do 3 in a row allowing about 3 minutes for the battery to recover between each test.
You can use a simple VOM to see amp draw. Most of those clamp type cost a bit for a VOM, so I would just get a small handheld carbon pile tester. You can do a lot more with one. Carbon pile to me is the best. It's simple, affordable and they last. I got this one when I worked at O'Reilly several years ago and I've abused it quite regularly.
LOAD TESTER