A trim fastener, comprising: a first fastener portion including: a component engagement head connected to a post; and first and second deflecting wings (26, 28) connected to an end of the post opposite to the head, each elastically deflectable toward the post and having a wing extending member (66, 68) facing the engagement head; and a resilient material second fastener portion connected to the first fastener portion, including: first and second wing enclosure elements (36, 38) connected to the wing extending member (66, 68) of each of the first and second deflecting wings (26, 28); and first and second through bores (40, 42) oppositely positioned about the post each temporarily receiving a portion of one of the first and second wing enclosure elements (36, 38) when the first and second deflecting wings (26, 28) elastically deflect toward the post, characterized in that the second fastener portion includes: a first resilient seal member having a concave seal surface defining a cavity directed away from the engagement head; and a second resilient seal member integrally connected to a seal surface of the first resilient seal member, the second resilient seal member including the first and second wing enclosure elements (36, 38) and the first and second through bores (40, 42). a first fastener portion including: a component engagement head connected to a post; and first and second deflecting wings (26, 28) connected to an end of the post opposite to the head, each elastically deflectable toward the post and having a wing extending member (66, 68) facing the engagement head; and a component engagement head connected to a post; and first and second deflecting wings (26, 28) connected to an end of the post opposite to the head, each elastically deflectable toward the post and having a wing extending member (66, 68) facing the engagement head; and a resilient material second fastener portion connected to the first fastener portion, including: first and second wing enclosure elements (36, 38) connected to the wing extending member (66, 68) of each of the first and second deflecting wings (26, 28); and first and second through bores (40, 42) oppositely positioned about the post each temporarily receiving a portion of one of the first and second wing enclosure elements (36, 38) when the first and second deflecting wings (26, 28) elastically deflect toward the post, first and second wing enclosure elements (36, 38) connected to the wing extending member (66, 68) of each of the first and second deflecting wings (26, 28); and first and second through bores (40, 42) oppositely positioned about the post each temporarily receiving a portion of one of the first and second wing enclosure elements (36, 38) when the first and second deflecting wings (26, 28) elastically deflect toward the post, characterized in that the second fastener portion includes: a first resilient seal member having a concave seal surface defining a cavity directed away from the engagement head; and a second resilient seal member integrally connected to a seal surface of the first resilient seal member, the second resilient seal member including the first and second wing enclosure elements (36, 38) and the first and second through bores (40, 42). a first resilient seal member having a concave seal surface defining a cavity directed away from the engagement head; and a second resilient seal member integrally connected to a seal surface of the first resilient seal member, the second resilient seal member including the first and second wing enclosure elements (36, 38) and the first and second through bores (40, 42).