It does not state on the event page http://www.bungie.net/en/event/ironbanner if previous Iron Banner items add the 10% boost to reputation.
I ranked up in the last Iron Banner and know that it is reset in this version, but I still have the Emblem, Shader, & Class Item and want to know if they supply the same boost or do I have to buy the 12/16 version of those?
-Edit-
I can confirm that the old items do work and stack the 10%. Here is the stats I saw yesterday...
Base Reputation (Can include the % reputation gains)
50 = Iron Banner Win
40 = Medallion of Iron or up to 5 x Match Loss
100 = Iron Banner Bounty up to 6 per day
Reputation Gains (They will stack)
10% = Sigil of the Iron Lords (Rank 1 Emblem)
10% = Million Million (Rank 2 Shader)
10% = Scar of Radegast (Rank 3 Emblem)
10% = Class Item (Rank 5)
10% = Tempering Day 1 (Increase per day to 15%, 25%, 40%, 60%, 85%, 115%)
I did have odd stuff happen where I did not get 100 Rep for the "Hard Forged" 10K XP Bounty, and with the "Iron Embrace" Bounty I had an emblem on and it did not stack the 10%. There was also a win w/ +1 loss that gave zero rep when it should have been 90 rep.
In theory for today if you have the 3 items plus the tempering @ 45% you should get..
72.5 = Win
58 = Each loss (Max 362.5 for 1 win + 5 losses)
145 = For each bounty
By Monday @ 145%...
122.5 = Win
98 = Each loss (Max 612.5 for 1 win + 5 losses)
245 = For each bounty
Rank 5 = 8500 Reputation Total
170 = Wins (No Rep Gains or Bounty)
34 = Wins + 5 Losses Each (Assuming your luck is bad and you get 5 losses for each win @ 250 rep)
118 = Wins (45% Rep if you started today)
70 = Wins (145% Rep if you started Monday)
You can get more than 50% of the reputation from bounties alone if you are able to get them each day.