No, I remember once that Lily said she used titanium to make the cockpit of the Phoenix, nothing about the Enterprise. Also, federation ships are made out of tritanium, not titanium. Although it's not a real alloy, in Star Trek it is. If the did mention what the Enterprise is made out of they said tritanium, you just heard wrong.
When first looking around the ship, astonished by the size of it, Lilly makes a reference to how long it took her to find enough titanium for "a four meter cockpit" (referencing the Phoenix). There's no actual reference to the Enterprize being made of titanium.
I would like to assume the following:
1) Tritanium is a variant of titanium
2) Tritanium shares many of the qualities of titanium, while being stronger (somehow)
3) The Enterprise has its outer skin made out of tritanium
Nowhere in there does it assume that the Enterprise is only made out of tritanium. There could easily be magnetic materials just below the skin, for the boots to attract.
I commented on this on the other slip-up about sparks falling to the hull in zero gravity. Regardless of whether the hull material is magnetic, if the hull were polarised (as seen in ST:Enterprise) it may cause the hull to be magnetic anyway. I know they never use the term polarise the hull plating in any other trek, but it may be such a trivial thing on modern ships, that it can stay polarised without much power drain