slippingaway,
Yes, slide assembly is the correct term. As I was reading your post, I thought of just a few more items.
As I write this I have the instruction manual open so I should use the correct terms.
The gas block assembly has a top and bottom. It has 4 screws that attaches the top and bottom gas block assembly. I have seen several cases of one of the 4 screws breaking off. When this happens the top portion has the threads part of the screw. I replace the top and use new screws. I would have a few of those screws and the top portion of the gas block assembly. Part # 5. Top and bottom.
Slide springs wear over use and I normally replace them following a season of shooting. Part # 19.
Storing the rifle with the bolt closed will preserve the life of the Slide Spring.
To be honest, you might never need any of these parts. The rifles that I work on have served on a range for years and have seen more service than the typical rifle in the hands of the average user.
If I had a mini and was going to keep it and shot it, I would have the parts I listed.
Bill