Not sure about this, every syllabic ḷ should have underwent the ḷ > ol > la change if that was the case.
What is the datation of Macedonian ḷ > ol change?

Well, the word "Bulgarian" can help us here.

In the Bitola Inscription (1015 AD):


We still have the forms withthe yer: блъгарьскомь, бльгаромъ, бльгарїнь etc.

Linguists believe that the sequence ль was actually pronounced as /l./ with the liquid resonant, as for example, the Czech river Vltava:


Which the Bulgarians spell as: Вълтава


So after that time we have the Serbo-Croatian evolution of Bl.garin > Bugarin as in vl.k>vuk and the Bulgarian pair Bъlgarin, vъlk.

The Macedonian expected term Bolgarin (as in volk) exists, but it is attested very lately, in the 19th century, although the majority of the Macedonians had borrowed the serbian form Bugarin as their endonym.

For example, in Marko Cepenkov's stories the terms "Bugarin" and "Bugarski" are widespread:


reference #4: In Cepenkov's tales a Macedonian speaking Christian is a Bugarin, a Macedonian speaking Muslim is a Pomak … and the Macedonian language is called Nashincki or Bugarcki. "Developing cultural identity in the Balkans: convergence vs divergence", Raymond Detrez, Pieter Plas, Peter Lang, 2005, ISBN 90-5201-297-0, p. 27.

However, in many authors like Kuzman Shapkarev and Partenij Zografski we find the terms Bolgarin/Bolgarski, which as I said are the linguistically "correct" terms (the ones that agrees with volk, polno etc):


Now Bugarin/Bugarski is "correct" from someone from the Skopje-Kumanovo region who also said vuk,puno.
Bolgarin/Bolgarski is "correct" in those dialects that were used for the codification of Macedonian.
Bъlgarin/Bъlgarski is "correct" in those dialects that had a phonemic schwa (as the southern and eastern ones did/ still do).

However, note that according to Friedman, there are some western dialects who still preserve the liquid resonant /l./ (vlk).