The cosmetic difference of the infantry can be overlooked (or covered with clever basing to hide the leg wrappings), however the biggest difference between the French and the Poles is the machinegun itself. The Poles used a bulky Browning machinegun as you can see on the comparison picture. I do think it is easy enough to fix this by adding greenstuff to make the cooler on the Browning. At this scale and tabletop distance, no one will notice.
With all that explained, the Forged in Battle models are once again crisp and very high quality castings. The blister contains 4 HMG teams, but no command team. With the very imminent release of Polish dismounted cavalry (and 10th motorized cavalry brigade) I think you will be able to scavenge a command team or two if need be for this blister. Of course you could also attach the HMG teams to the cavalry companies in which case you won't need a specific HMG platoon commander.
It's a good buy in any case, quality miniatures at a good price. Just remember the Forged in Battle stuff does not come with any bases so you will need to purchase that elsewhere. Either Battlefront original bases of laser cut MDF bases from Warbases.co.uk
The comparison pictures show the FiB French HMG team with my FiB Polish HMG team and Battlefront Polish HMG team, as well as with some FiB mounted cavalry.