I believe we now only use [oK] to designate forms which contain 旧自体 kanji.

@@ -12 +11,0 @@
-<ke_inf>&oK;</ke_inf>

纏りつく	38	0.0%
纏り付く	145	0.1%

There was a 2019 suggestion to maybe [oK] 纏り付く. On the ngrams and absence in most modern references, I think [sK] could also apply.  

Anyway, it would minimally be nice to know at a glance that it is no longer considered correct (which seems uncontroversial. not in sankoku, not in daijs, not in any kotobank or weblio references, super-low on ngrams).

=== non-critical observations on readings follow

Was surprised at the relative commonness of the まつ variant. Appears in sankoku only as a reference(but it *is* still there):
 纏(まつ)わり付く→纏（まと）わり付く

this seems to reverse the ordering from daijs, which keeps the historical-but-less-popular form as the main headword.

@@ -11,0 +12 @@
+<ke_inf>&oK;</ke_inf>

I prefer this version. I'll reject the later edit.

Google N-gram Corpus Counts
╭─ーーーーーー─┬────────┬───────╮
│ まとわり付く │ 10,617 │  9.3% │
│ 纏わりつく　 │  8,326 │  7.3% │ - sK
│ 纏わり付く　 │  4,790 │  4.2% │ - (in daijr/s, koj, shinmeikai)
│ まつわり付く │    213 │  0.2% │ - sK
│ 纏り付く　　 │    145 │  0.1% │ - (in daijr, shinmeikai)
│ 纒り付く　　 │      0 │  0.0% │ - drop (itaiji)
│ 纒わり付く　 │      0 │  0.0% │ - drop (itaiji)
│ まとわりつく │ 86,498 │ 75.8% │
│ まつわりつく │  3,486 │  3.1% │
╰─ーーーーーー─┴────────┴───────╯

Simplifying restrictions

@@ -8,3 +7,0 @@
-<keb>纏わりつく</keb>
-</k_ele>
-<k_ele>
@@ -12,3 +8,0 @@
-</k_ele>
-<k_ele>
-<keb>まつわり付く</keb>
@@ -20 +14,2 @@
-<keb>纒り付く</keb>
+<keb>纏わりつく</keb>
+<ke_inf>&sK;</ke_inf>
@@ -23 +18,2 @@
-<keb>纒わり付く</keb>
+<keb>まつわり付く</keb>
+<ke_inf>&sK;</ke_inf>
@@ -27,3 +22,0 @@
-<re_restr>まとわり付く</re_restr>
-<re_restr>纏わりつく</re_restr>
-<re_restr>纏わり付く</re_restr>
@@ -33 +25,0 @@
-<re_restr>纏わりつく</re_restr>
@@ -35 +27 @@
-<re_restr>まつわり付く</re_restr>
+<re_restr>纏り付く</re_restr>

まとわり付く	10617
纏わり付く	4790
纏わりつく	8326
まつわり付く	213
纏り付く	145

Could possibly have "oK" on the last two.

@@ -8 +8 @@
-<keb>纏わり付く</keb>
+<keb>纏わりつく</keb>
@@ -11 +11 @@
-<keb>纏わりつく</keb>
+<keb>纏わり付く</keb>
@@ -27,0 +28 @@
+<re_restr>纏わりつく</re_restr>
@@ -29 +29,0 @@
-<re_restr>纏わりつく</re_restr>
@@ -32,0 +33 @@
+<re_restr>纏わりつく</re_restr>
@@ -34 +34,0 @@
-<re_restr>纏わりつく</re_restr>

daijirin (1) https://kotobank.jp/word/纏わり付く・纒わり付く-388490 (2) https://kotobank.jp/word/纏り付く・纒り付く-388348#E5.A4.A7.E8.BE.9E.E6.9E.97.20.E7.AC.AC.E4.B8.89.E7.89.88
kenkyusha https://ejje.weblio.jp/content/纏わり付く

The amount of variants is incredible

@@ -14,0 +15,9 @@
+</k_ele>
+<k_ele>
+<keb>纏り付く</keb>
+</k_ele>
+<k_ele>
+<keb>纒り付く</keb>
+</k_ele>
+<k_ele>
+<keb>纒わり付く</keb>
@@ -33,0 +43,2 @@
+<gloss>to surround</gloss>
+<gloss>to cling to</gloss>

Probably not.

@@ -16,3 +15,0 @@
-<k_ele>
-<keb>纒わり付く</keb>
-</k_ele>
@@ -24 +20,0 @@
-<re_restr>纒わり付く</re_restr>
@@ -31 +26,0 @@
-<re_restr>纒わり付く</re_restr>

not iK.  itaiji.  however 纒わり付く gets 44 google hits, including many edict-dervied ones.  is it worth recording at all?

@@ -18 +17,0 @@
-<ke_inf>&iK;</ke_inf>

Ngrams. The JEs point まとわりつく to まつわりつく and do all their examples as kana (まつわりつく), but the n-grams show that the まとわりつく versions are more common.

@@ -3,0 +4,3 @@
+<k_ele>
+<keb>まとわり付く</keb>
+</k_ele>
@@ -10,0 +14,3 @@
+<keb>まつわり付く</keb>
+</k_ele>
+<k_ele>
@@ -15 +21,5 @@
-<reb>まつわりつく</reb>
+<reb>まとわりつく</reb>
+<re_restr>まとわり付く</re_restr>
+<re_restr>纏わり付く</re_restr>
+<re_restr>纏わりつく</re_restr>
+<re_restr>纒わり付く</re_restr>
@@ -18 +28,5 @@
-<reb>まとわりつく</reb>
+<reb>まつわりつく</reb>
+<re_restr>纏わり付く</re_restr>
+<re_restr>纏わりつく</re_restr>
+<re_restr>まつわり付く</re_restr>
+<re_restr>纒わり付く</re_restr>
@@ -22,0 +37 @@
+<misc>&uk;</misc>