not sure what you mean by "legitimate"?
L/B have lodged a Formal Offer.
Because of that L/B must comply with all sorts of rules under Corps Act and ASX Listing Rules.
L/B must keep the bid open for a certain time, and they cannot withdraw the bid.
L/B must pay all s/h who accept, IF the Conditions of the bid are met.
so it is "legit" in that sense.
But who knows what schemes L/B is up to?