Yes, barrel location and age will affect similarity among whiskies, and ETL is reputedly around the same age as the Lot B (10-14 years). However, the mash bill, yeast, type of still, proof off the still, barrel entry proof, and barrel char will also play a part, and that list is hardly exhaustive. I suspect most of us would find the closest resemblance among the whiskies with the same mash bill and yeast, but these will also tend to have the same proof off the still, barrel entry proof, and barrel char, as they come from the same distillery. As a consumer, it's actually hard to know what variables matter (and how) without the sort of work being done by Buffalo Trace with their Single Oak project.
It's also possible that your palate is "calibrated" differently from others. Most of us have tasted many whiskies from many distilleries, and so have a sense of the range among them, which can also help to define a distillery "character." For instance, I don't have much trouble discriminating Buffalo Trace, Heaven Hill, Beam, or Four Roses products from one another. To me, Buffalo Trace and Eagle Rare 10 are certainly similar when tasted head to head, and the same goes for Booker's vs. Baker's vs. Knob Creek, or any of the Four Roses single barrels (w/ different mash bills and yeasts, no less). Mixing and matching between distilleries, however, shows how different they can be (though surprisingly less often than you might think).
All of this to say that you might profit from arranging a few head to head tastings of your own, using comparison whiskies from both the same and different distilleries, as well as similar vs. different mash bills, ages, etc. I've learned a lot that way.