The stones you have bought look fine. With Baltic amber you will often see a lot of small cracks in the surface, stelate trichromes (those hairy 'bunches') etc. Really, you get what you pay for. You've bought an inexpensive couple of specimens. The pieces of amber that they are in are small and the insects are also small. I wouldn't worry. The supply of Baltic amber pieces with small inclusions is plentiful and it would be more hassle than it is worth to fake these specimens for a couple of pounds.
It's the specimens that contain large inclusions and rare inclusions, that are free from any flaws and look too good for the price that you need to watch out for.
A very good test is to see if the amber fluoreses in UV light. That's a good sign. Also, does it float in very salty water? - It should.
Hope this helps, Joe
Fossils are great.