I believe these routers are 2T2R, however not sure. These routers have one radio for 2.4Ghz and one for 5Ghz. Send and receive.
However replacement of the antennas is probable. Most of the antenna connector are standard gold connectors with center pin is male I believe. However placing them far away from each other might be unwise as I think the wifi uses both antenna for transmission and reception. Are you trying to get signal to places in the house? I would recommend if your looking to extend radio range that you might think about a AP device such as DAP-1525 or similar to help you get signal farther from the router.