See Archae's answer at "another place". There can be significant variability in stone from the same quarry. Look at the Sphinx, for example. The different layers in the rock were laid down at different times and have different properties.

Baalbeck is Roman - the excavations in the 20th century have clearly shown that. If it predated the Romans then there'd be traces such as pottery.

The Egyptians were past masters at moving large stones, the unfinished obelisk at Awwan would have been 1100+ tons and they would have floated that down the Nile to Luxor and erected it at Karnak. They could easily have shifted tiddlers of less than 800 tons - that's about the same size as the Collossi of Memnon (c. 700 tons) and less than the "Ozymandius" statue of Ramesses II ( c. 1000 tons).

But if it had been (originally) an Egyptian structure there'd be Egyptian pottery/artefacts.

Baalbeck is zero use to support any sort of LC !

John