Generally not. Competent operation of a process that can be taught in weeks is skilled work rather than specialized knowledge, and difficulty recruiting locally is not a factor the classification considers.
The training question answers the eligibility question
A practical test that employers can apply themselves is to ask how long it would take to bring a capable new hire to the level of the person proposed for transfer, and what would have to be transferred to do it. If the answer is a fortnight of shadowing and a written procedure, the knowledge is not specialized in the sense the rule uses, however reliable the employee is. If the answer is that nobody could be brought to that level without years inside the organization, because the knowledge includes undocumented judgement about why the process behaves as it does, the case is worth building. Employers should also be candid that the honest answer sometimes disqualifies the person they most want to send. That is information worth having before a fee is paid, not after a denial arrives.
Hypothetical example: Pavel developed calibration methods for a Canadian manufacturer of precision irrigation valves and is proposed for its U.S. facility. A first review should identify the methods, the documents he created, the years of use, and the small group able to replicate them. Technical change logs and training records settle the knowledge claim; payroll and corporate records settle the separate transfer conditions. The company should explain why his expertise is advanced or organization-specific without claiming that every capable technician is a specialist. The usual failure is a narrative about general skill that never identifies what the employee knows that is not readily available.