Don't have specs on the #37 but this may, or may not help!
W.R. Weaver Company Mount Base Specifications
DETACHABLE MOUNT BASES
No. of Base Length Hole Spacing Diameter Thickness
11 .812 .504 1.290 .147
12 .812 .504 .925 .155
13 .812 .504 .730 .238
14 .812 .504 Tapered for Savage 99 only
15 .812 .504 .946 .195
16 .812 .504 .840 .205
17 .812 .504 .770 .219
18 .812 .504 1.050 .182
19 .812 .504 1.160 .125
20A 1.168 .860 1.360 .127
21 .812 .504 .710 .273
22 .812 .504 .700 .201
24 .812 .504 .900 .271
25 .812 .504 1.125 .248
27 .812 .504 .930 Tapered .161/.185
28 .812 .504 Flat .239
29 .812 .504 Flat .292
30 .812 .504 .845 Tapered .205/.230
31 .812 .504 Octag. .182
32 .812 .504 Octag. .357
35 1.168 .860 1.290 .147
36 1.401 .604 3.900 .272
39 .812 .504 Flat .165
40A 1.840 .860 1.290 .147
42 .812 .504 .730 .298
43 .812 .504 .840 .265
44 .812 .504 .770 .279
45 .812 .504 1.050 .396
46 1.168 .860 1.290 .222
47 1.168 .860 2.692 .368
48 .812 .504 1.290 .395
49A 1.058 Win. 70 in 375 H&H, 300 H&H only .368
50 4.500 .504 Flat-Tapered .200/.232
53 4.983 Win. 88, 100 1.290 .222
54 .812 .504 1.290 .222
55 .812 .504 1.050 .310
57 2.340 .960 1.220 .250
58 4.624 3.275 Flat .283
59 .812 One hole only Notched .366
60 4.500 Browning .22 Auto, H&R "Topper" .361
61 1.168 .860 Flat .360
62 4.430 Rem. 740, 760 1.290 .222
63A 6.125 Marlin 336 Flat .283
63B 5.450 Marlin 336 Flat .370
65 2.000 None Spec. * .322
66 2.650 None Spec. * .322
67 1.650 None Spec. * .332
68 .812 .504 .916 .399
70 5.900 Rem 600 1.290 .275
71 1.168 .748 1.180 .215
72 .812 .504 2.590 .376
74 5.723 Savage 24V 1.125 .275
75 1.168 .860 1.050 .310
76 .812 One hole only 1.050 .310
77 .812 .504 .700 Tapered .248/.267
78 .812 .504 .880 Tapered .171/.198
79 .912 .604 3.900 .272
80 6.125 .500 1.892 .147
81 6.000 H&R 360, 361 .946 Tapered .237/.252
82 6.000 H&R Topper 158C 1.050 .396
83 .812 .504 1.252 .250
84 1.168 .860 1.252 .250
85 1.168 .860 1.124 .275
86 .862 .555 .925 Tapered .366/.396
87 5.000 H&R 700 1.050 .400
88 5.900 Mossberg 500AS 1.500 .496
89 .862 .560 1.062 .347Fr/.301Rr
90 5.000 Marlin 39A .300Fr/.428Rr
91 1.400 .504 .946 .280
92 4.500 Thompson Contender Hand Gun .361
93 4.430 Rem 4/6/7400/7600 1.290 .222
94 .812 .500 1.124 .170
95 1.168 .860 1.124 .170
TO-9 4.750 Ruger 10/22 2.000 Tapered .155/.170
TO-10 5.00 Grooved for most 22's Spec. * .175
Simple math tells us the #37 probably has a thickness of .293". I believe I have some out in the shop. Those would be lower mounts than the 46/47 combo..
