To answer the question "Is it always a scam if they ask?:" -> No, it isn't
But for this ad you have the following red flags:
* Nothing when googling the phone #
* No ECCIE reviews on the phone #
* No TER reviews on the phone #
* BB services on the ad (assuming BBFS not BBBJ as that should be considered standard)
I wouldn't touch that with a 10 foot pole and any deposit request is a scam