Can a Soldier who recently went active duty after a break in service from the reserves be awarded the AGCM within the first year of AD ?

Hypothetically, yes.
The first award of the AGCMDL can be awarded after 1 year, but less than 3. But only if the Soldier is discharged. If he is staying on AD, he has to wait 3 years like everyone else.
See AR 600-8-22 para 4-5c-e

Yes

Here you need to ask your unit clerk at AG (adjutant general/personnel). They will have the correct answer. If you qualify they will start the paperwork for the award.