FAR Part 12 is silent with regards to notification to unsuccessful offerors. However, under FAR Part 15 acquisitions, not only is the CO required to notify unsuccessful offerors (15.503), but are also required to specifically notify unsuccessful offerors for small business set-asides. Under FAR 15.503(a)(2) the CO must disclose the apparently successful offeror and provide an opportunity to all offerors to protest the size status of the business in accordance with FAR 19.302.
In reading FAR 19.302, it specifically calls out FAR Parts 14 and 15 regarding the protest period, but does not speak to FAR Part 12 at all.
Based on reading the regulation, it does not appear that awards made under FAR Part 12 require a pre-award notification to unsuccessful offerors (small business or otherwise).
Let me point out that the acquisition I'm referencing is a large (>$50M ID/IQ) LPTA award for commercial "widgets". Thoughts?