These questions are generally answered quite quickly by cursory investigations of the BLC page ... as you can see from the map, the property/parcel is nearly enveloped on the east and north by the Bay State Road historic preservation district, and then Fenway Park to the south has landmarked status. But it itself is totally at the mercy of the proverbial wrecking ball!
Also, BLC site maintains the list of all landmark petitions submitted thru last May, and their statuses. Annoyingly it is non-sortable being a static PDF, but still.
Finally, I'm noticing that the tax designation/status of this parcel is very weird
(suspicious?)
Apparently, as a "Condo Main Building" usage, it hasn't been taxable (i.e., commercial) property, in DECADES. Whiskey Tango Foxtrot? Perhaps someone with some expertise in this realm can make some informed speculation. I sure can't...
Looks like the rooms and restaurant spaces are each taxed as individual commercial units.
https://www.cityofboston.gov/assessing/search/?q=645+beacon