When was the last time two teams, in their first SB appearance, opposed one another?

BOLD denotes the first time the team has been in the Super Bowl.

*** denotes both teams first time being in the game.

(Note, the first time means the franchise, not in the case of the Rams, Raiders, Colts or Ravens who have been in the game representing two cities. The Baltimore Ravens were the original Cleveland Browns.)

1. Green Bay 35, Kansas City 10 ***

2. Green Bay 33, Oakland 14

3. New York Jets 16, Baltimore 7 ***

4. Kansas City 23, Minnesota 7

5. Baltimore 16, Dallas 13

6. Dallas 24, Miami 3

7. Miami 14, Washington 7

8. Miami 24, Minnesota 7

9. Pittsburgh 16, Minnesota 6

10 Pittsburgh 21, Dallas 17

11 Oakland 32, Minnesota 14

12 Dallas 27, Denver10

13 Pittsburgh 35, Dallas 31

14 Pittsburgh 31, Los Angeles Rams 19

15 Oakland 27, Philadelphia 10

16 San Francisco 26, Cincinnati 21 ***

17 Washington 27, Miami 17

18 Los Angeles Raiders 38, Washington 9

19 San Francisco 38, Miami 16

20 Chicago 46, New England 10

21 New York Giants 39, Denver 20

22 Washington 42, Denver 10

23 San Francisco 20, Cincinnati 16

24 San Francisco 55, Denver 10

25 New York Giants 20, Buffalo 19

26 Washington 37, Buffalo 24

27 Dallas 52, Buffalo 17

28 Dallas 30, Buffalo 13

29 San Francisco 49, San Diego 26

30 Dallas 27, Pittsburgh 17

31 Green Bay 35, New England 21

32 Denver 31, Green Bay 24

33 Denver 34, Atlanta 19

34 St. Louis 23, Tennessee 16

35 Baltimore (Ravens) 34, New York Giants 7

36 New England 20, St. Louis 17

37 Tampa Bay 48, Oakland 21

38 New England 32, Carolina 29

39 New England 24, Philadelphia 21

40 Pittsburgh 21, Seattle 10

41 Indianapolis 29, Chicago 17

42 New York Giants 17, New England 14

43 Pittsburgh 27, Arizona 23

44 New Orleans 31, Indianapolis 17

45 Green Bay 31, Pittsburgh 25

46 New York Giants 21, New England 17

47 Baltimore 34, San Francisco 31

48 Seattle 43, Denver 8

49 New England 28, Seattle 24

50 Denver 24, Carolina 10

51 New England 34, Atlanta 28

52 Philadelphia 41, New England 33

53 New England 13, Los Angeles Rams 3

54 Kansas City 31, San Francisco 20

55 Tampa Bay 31, Kansas City 9

56 Los Angeles Rams 23, Cincinnati 20

Source: http://www.espn.com/nfl/superbowl/history/winners

So from my research, the last game that both teams were new to the game was SuperBowl 16 in 1982. There are four teams in the NFL who have never been to the Super Bowl, Detroit, Cleveland, Houston and Jacksonville. The only way to get two new teams in the Superbowl is for Detroit (the only NFC team) to play Cleveland, Houston or Jacksonville in the AFC.

I appreciate that thorough analysis Yong Fang.

Moving of franchises is interesting, as you've mentioned; for example, if the Raiders go to a Super Bowl, they will become the first Las Vegas team to appear. Of course, they were previously AFC champs as both the Oakland Raiders and L.A. Raiders.