Run Scores on Inning-Ending Double Play

 
One out and R3 is on third base and R1 is on first base. R1 is stealing on the pitch, but the batter hits a high pop to center field which is caught for the 2nd out of the inning. R1 had left 1st base well before the center fielder caught the pop-up, so R1 begins to return to 1st base. The ball is thrown to 1st base before R1 returns to 1st base, so R1 is out and the double play ends the inning. R3 properly tagged up and scored well before the double play at 1st base ended the inning. 

Was R1's out at 1st base a force out or a timing play? Does R3's run count?

Call
A run does not count when a half-inning ends on a force out. However...
 
While it appears that R1 is "forced" to return to 1st base, this is NOT a force play. The force of R1 was removed when the batter was retired on the pop-up. R1 must return to 1st base in order to not be at risk to be called out (for not properly tagging up).  
 
So... this is a timing play. Since R3 scored before R1 was put out at 1st base, R3's run scores.