Terrace Side Thru Wall Sleeve Bolted In So Can A/c Be Safely Used In Sleeve?

can a frigidaire thru the wall airconditioner be installed in the chrysler thru the wall sleeve, but keep the original to building thru the wall outside on terrace a/c sleeve cover which is bolted in with nuts and bolts in place? there have been many push in a/c robberies from renters who come and go and share a terrace, so many tenants in my niece's apartment house said they opted for security reasons to leave the outside sleeve cover in tact and just install their a/c's thru the sleeve, and they also said to date the frigidaire a/c's work great with no problems while in the fan and cooling modes. would this be an acceptable safe installation with no problems as far as safely installing and using the frigidare 10,000 btu air conditioner? please advise as i have seen building which have the same outdoor sleeves in place even without terraces, but the occupants do have a/c's in full operation thru those a/c sleeves. thanks in advance.