I have seen a few post around lately about the impact in the changes in SMW 1.6.x on impacting the Record types (i.e. not being positional anymore). However I haven't found yet any doc or comment about what's the new syntax for accessing Records elements, i.e. in a #show sentence, in case there's any.
Any help will be welcome as this has broken several templates in our Wiki and I would prefer to not have to switch to SIO and then back to native subobjects when they are ready for prime time.
The parentheses are unnecessary, I agree. I made a bug report about them in another case, and if you agree they should be removed in your case too (in the factbox), please add your comments about it to this bug report:
About getting your query to work, I have not tried this type of property and query yet. But, I think maybe the upcoming SMW 1.7 might address this issue with its native built in support for semantic internal objects: