According to my records, your rifle was probably manufactured in mid-to-late 1954 and would have a "F" Lever Boss Code ("LBC") on the lower, front of the receiver. Here's an excerpt from my records:
F= 1954: 686489(19F), 704960(13F), 7184xx, 727303(13F), 747330(14F), 751488(?3F),7567xx(5F),
Use a magnifying glass to look at your rifle's LBC. Most LBCs were very lightly embossed on the front of the lever boss, just in front of the bolt on which the lever rotates. Often, only part of the OVAL in which the LBC is stamped will show, sometimes one can see the whole OVAL (not a circle). The LBC will show up as a number (the inspector's number) followed by the letter indicating the year of manufacture. Note your rifle's serial number falls well within 1954 as the year of manufacture.
However, that said... it must be noted that NOTHING is "for sure" with Savage. There were times when, for some unknown reason, Savage employees would pull an individual rifle off the line and put it aside. It might sit there for a year or several years before that rifle was put back on the line and finished thus throwing the serial number of that individual rifle out-of-sequence. To the best of my knowledge, no one has ever figured out why this was done.
Therefore, the best way to determine the year-of-manufacture is by noting the Lever Boss Code (LBC) which tend to be more accurate in determing the year-of-manufacture than the rifle's serial number.
Savage began using the LBC in 1949 with the letter "A". In 1950, that letter inside the OVAL was changed to "B", changed to "C" in 1951, "D" in 1952, "E" in 1953, "F" in 1954 and so on. The letters "O" and "Q" were skipped due to their very similar appearance. Savage ceased using LBCs in 1971 ending with the letter "Y".
Since you indicated you saw an "I" on the lever boss, I suggest that could be the letter "F" with the cross bars missing. However, if you are absolutely SURE it is a letter "I", then look for the inspector's number immediately in front of the letter"I"... and, yes, the letter "I" in the LBC indicates a 1957 year-of-manufacture.
However, as stated previously, that letter should be inside an OVAL with the inspector's number in front of the letter "I". Since these OVALS and LBCs were very lightly embossed, it is possible that ONLY the letter "I" would show. However, that is unlikely... thus my suggestion that you use a magnifying glass to look at the LBC.
I hope this helps...
Strength & Honor...
Ron T.