If you're talking about being non-vol, they usually get enough volunteers to cover the vacancies. New hires who volunteer get significant benefits for doing so. 2nd year pay, paid move both ways if you stay 36 months, not to mention the $3000/mo everyone gets.

B-1 Pilots staffed to flying positions in the Guam Base shall receive, in addition to all other compensation, a Foreign Base Allowance in the amount of $3,000 per month for each month of Active Service.

B-1-b At his option, a Pilot assigned to Guam who is in his first year of employment shall receive an eighteen (18) month Base freeze and be paid using the second-year pay rate (in Status), or no Base freeze and be paid using the first-year pay rate.

H-2 Pilots transferring or assigned to the Guam Base shall be entitled to a paid move to Guam, provided they remain in Guam for a minimum of eighteen (18) months of Active Service.

H-3 A Pilot who received a paid move to Guam and has provided thirty-six (36) months of Active Service on Guam shall be entitled to a paid move from Guam.