While purchasing a refurbished MacBook Pro, does the model year make a difference?

Yes, the model year does make a difference.

It makes a difference as to

• The specifications of the machine
• What versions of macOS it will be able to run
• How long you're likely to be able to get parts and repair service for it (if necessary)
• Whether you get a Mac with the infamous butterfly-switch keyboard. That keyboard design turned out to be a bit prone to trapping dirt in ways that caused keyboard malfunctions that were were expensive to repair. Apple once offered a keyboard service program . That program has expired, but the article is still useful inasmuch as it has a list of the Intel-based Mac notebooks that had the butterfly-switch keys.

If you are considering getting a used MacBook Pro, I would suggest looking at Certified Refurbished machines from Apple. According to Apple, these include

• A one-year limited warranty
• Full functional testing, genuine Apple part replacements (if needed), and a thorough cleaning
• The original operating system or a more recent version
• All accessories and cables repackaged in a brand‑new box

Certified Refurbished Products - Apple

A "refurbished" Mac sold by some unknown third party might be little more than a used machine tossed into a box.

Here are some considerations. The size of the Mac's hard dive is important, as is the amount of RAM it has. Some older models can only run certain older operating systems, and they may not be able to work with certain newer versions of apps. And older versions may be no longer available.

I'm not sure what you are asking. Different model years have different specifications and may have different prices. Please explain further what it is you wish to know.

Regards.