I'm not sure exactly what you mean by "dust collection part". The only thing that it comes with besides what you see in the stock picture is 5 pocket hole plugs. I attached a picture of the back of the tool, as that looks like you might be able to cradle a vacuum hose somehow, but I haven't tried to confirm that's possible.
Yes, there are measurements on the base to adjust based on the size of lumber.
This rebate is now expired. Home Depot nor Kreg will honor this rebate although both Home Depot and Kreg continue to advertise the rebate. 1/31/20 expired.
No, no case. It would definitely be nice if there was at minimum a small case of some sort for the accessories (drill bit, mobile clamp, etc.).
This does accumulate a lot of sawdust, especially when drilling multiple holes. I don't have the dust collection adapter, but after seeing the mess it made I will probably buy the adapter. It just saves time during cleanup.
Kregs website just states "while supplies last" so not exactly sure.
These items still exist and just are out of stock in some places. I cannot give a specific time as to when they will be back in stock. My best speculation is towards the end of September to the middle of October. It could possibly be sooner. You can also visit the Kreg website periodically. Thanks!
Hello HD customer, Thank you for your recent inquiry with The Home Depot about the Kreg K4 Pocket-Hole System with Face Clamp, R3 Drill Guide and Pocket-Hole Screws (50-Pack). After review, we expect more later this month. You can add your email to the products page to be notified when its officially back in stock. We appreciate your business and look forward to serving you in the future. - From the HD team