Right now the signal is coming from the regular 99/103 satellites, so if you can get HD, you can get the 4k signal. Eventually you will need the RB LNB, but today the 4K is coming from the regular satellite.
As for equipment, you can buy and call to activate a HR54 or C61k with no trouble.
The challenge is getting 4K authorized on the account, which they generally do not do without a tech visit to install the new LNB and C61k.