From Random House:

Some usage guides object to the use of personnel as a plural. However, this use is well established and standard in all varieties of speech and writing. The use of personnel with a preceding number is largely restricted to business and government communications: "Six personnel were transferred".

So, some people will be comfortable using personnel in the way you describe (particularly in business), but others might not be. However, the fact remains that the usage you describe in the question has a strong precedent.

From Random House:

Some usage guides object to the use of personnel as a plural. However, this use is well established and standard in all varieties of speech and writing. The use of personnel with a preceding number is largely restricted to business and government communications: "Six personnel were transferred".

So, some people will be comfortable using personnel in the way you describe (particularly in business), but others might not be. However, the fact remains that the usage you describe in the question has a strong precedent.

(This is, of course, assuming you are using "personnel" to refer to people who work at the store, and not just any people in the store including customers.)

From Random House:

Some usage guides object to the use of personnel as a plural. However, this use is well established and standard in all varieties of speech and writing. The use of personnel with a preceding number is largely restricted to business and government communications: "Six personnel were transferred".

So, some people will be comfortable using personnel in the way you describe (particularly in business), but others might not be. It is something that is done, nonetheless.

From Random House:

Some usage guides object to the use of personnel as a plural. However, this use is well established and standard in all varieties of speech and writing. The use of personnel with a preceding number is largely restricted to business and government communications: "Six personnel were transferred".

So, some people will be comfortable using personnel in the way you describe (particularly in business), but others might not be. However, the fact remains that the usage you describe in the question has a strong precedent.