So what where the options? Wait till the regulatory body approved the sale? Nobody will think this is a google watch except the same people that follow tech news - and therefore know about the sale.
Just drop "a google company" from your website (which is where people are buying your products). That seems like the most sensible option, unless there's now some indication that the deal may not go through.
There are a lot of rules about what a sold company can do. IANAL but it probably makes the most sense to just act as though you're not sold until the deal is final.
