Toggle buttons bar for mobile?

I am designing filter interface that is located at the bottom of the screen of a smartphone.

I do not know if it's better to leave some space between the buttons (see the top of the attached image - preflop action), or leave the buttons without spacing/border (see bottom of the attached image - preflop position)

Is one button being selected enough indication of where a user is supposed to click to change the option, or is additional spacing needed?

Some additional info:

• One of the options is always selected
• Only one of the options can be selected
• Hover to show button borders does not work since this is targeting smart phones and tablets