No according to SOPUS.
Simplest distinction I can think of is GTL process uses methane as the initial feedstock, so synthesized GTL process molecules can have any number of carbon atoms, and a wide variety of shapes especially with regard to degree of branching for a given carbon number. However, with respect to lube base oils, additional processing via hydroisomerization aka catalytic dewaxing increases the degree of branching significantly.
PAO is manufactured uding ethylene as the basic bulding blocks so hydrocarbon molecules of PAO only consist of even numbers of carbon atoms (multiples of two). Molecular dtructure is more specific yo degree of branching. Begore being used as lube syock PAO is saturated with hydrogen to paraffins / alkanes for stability as olefins are fairly reactive species.
In the end both are highly branched hydroprocessed hydrocarbon mixtures when used as lube oil base stocks.
The question as posed regarding differences is really broad based and needs more narrowing down to be much more specific in providing an answer.