I purchased a 2010 189 Sport (new) from BPS is Independence, Missouri in May of last year. Like you the spec sheet said that it came with a Lowrance fish finder, but there was not one installed.
Here is what I did. I had to find the spec sheet that was on Bass Pros Site, took me a while and some extra searching through my internet history since BPS had taken it off their site. Once I had that in hand, I took it back into BPS, talked with the Manager in the Tracker Boat Sales Office area of BPS. He looked at it and said your right it does say there should be one. He had me bring the boat back at my convenience and they installed a Lowrance X-4 Pro Dual Search Fishfinder, not the best but it helped prevent an added expense at the time.
What he told me was, since the spec sheet listed it as a standard feature, they would pull one off the shelf and do the install at no cost. He was simply going to send an invoice to Tracker to recoup their money.
Hope that helps.