I can see no regulations in the NRMP which prevents programs asking candidates if they are interested in a pre-match contract; nor is there any restrictions on candidates from asking.
If you are seriously interested in a program and they have told you the same, I suggest you call or write the PD, express your interest, make mention of the fact that as an Independent DO candidate you are available for a pre-match contract (if that is what you want). You guys make it sound like junior high and wondering if someone else likes you; its OK to tell them you feel the same way, its even ok to say those 3 little words FIRST!
Bear in mind that not all programs offer contracts outside of the match as the NRMP does require them to offer 75% of their positions in the match. Also do not drop out of the match until you get a signed contract from a program that offers you one.