If there is a seller for 60,000 shares a/h, it must be a Market Maker? The price of the stock is in the $40-$45 range
It can be any market maker, person, institution, penson fund, hedgefund, investment bank, country, or any entity... but as far as your trading should be concerned, it doesn't matter one bit.
A market maker is not needed, as long as there is a buyer and a seller, and they agree on the price, the trade is done.
By the way, it is said that most of after hours trading, is done by computer algorithms; altough I dont know if there are some statistics to prove or deny this.