Yes, that was the first raid on the city.
A number of books state this, and I’ll list them below for further reference:
“Tested by Bomb and Flame: Leicester versus Luftwaffe Air Raids 1939-1945” by Austin J. Ruddy.
“But for These Things - Leicester and its People in WWII” by Vincent Holyoak
“Birds Eye Wartime Leicestershire 1939-1945: Maps and Aerial Photographs: A Synoptic View of Wartime Leicestershire” by Terence Clive Cartwright
“Birds Eye Wartime Leicester 1939-1945: A Synoptic View of Wartime Leicester” by Terence Clive Cartwright
“Wartime Leicester” by Ben Beazley
“The Blitz Then and Now - Volume 2” by Winston G. Ramsey
To list but a few.